Method for scheduling distributed virtual resource blocks

ABSTRACT

A method for efficiently scheduling virtual resource blocks to physical resource blocks is disclosed. In a wireless mobile communication system, for distributed mapping of consecutively allocated virtual resource blocks to physical resource blocks, when nulls are inserted into a block interleaver used for the mapping, they are uniformly distributed to N D  divided groups of the block interleaver, which are equal in number to the number (N D ) of physical resource blocks to which one virtual resource block is mapped.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/015,912, filed on Aug. 30, 2013, currently pending, which is acontinuation of U.S. application Ser. No. 12/850,575, filed on Aug. 4,2010, now U.S. Pat. No. 8,599,775, which is a continuation of U.S.application Ser. No. 12/349,470, filed on Jan. 6, 2009, now U.S. Pat.No. 7,808,949, which claims the benefit of earlier filing date and rightof priority to Korean Patent Application No. 10-2008-0131114, filed onDec. 22, 2008, and also claims the benefit of U.S. ProvisionalApplication Nos. 61/019,589, filed on Jan. 7, 2008, 61/028,186, filed onFeb. 12, 2008, 61/033,358, filed on Mar. 3, 2008, 61/037,302, filed onMar. 17, 2008, 61/024,886, filed on Jan. 30, 2008, 61/038,778, filed onMar. 24, 2008, 61/026,113, filed on Feb. 4, 2008, and 61/028,511, filedon Feb. 13, 2008, the contents of which are all hereby incorporated byreference herein in their entirety.

TECHNICAL FIELD

The present invention relates to a broadband wireless mobilecommunication system, and more particularly, to radio resourcescheduling for uplink/downlink packet data transmission in a cellularOFDM wireless packet communication system.

BACKGROUND ART

In a cellular orthogonal frequency division multiplex (OFDM) wirelesspacket communication system, uplink/downlink data packet transmission ismade on a subframe basis and one subframe is defined by a certain timeinterval including a plurality of OFDM symbols.

The Third Generation Partnership Project (3GPP) supports a type 1 radioframe structure applicable to frequency division duplex (FDD), and atype 2 radio frame structure applicable to time division duplex (TDD).The structure of a type 1 radio frame is shown in FIG. 1. The type 1radio frame includes ten subframes, each of which consists of two slots.The structure of a type 2 radio frame is shown in FIG. 2. The type 2radio frame includes two half-frames, each of which is made up of fivesubframes, a downlink piloting time slot (DwPTS), a gap period (GP), andan uplink piloting time slot (UpPTS), in which one subframe consists oftwo slots. That is, one subframe is composed of two slots irrespectiveof the radio frame type.

A signal transmitted in each slot can be described by a resource gridincluding N_(RB) ^(DL) N_(SC) ^(RB) subcarriers and N_(symb) ^(DL) OFDMsymbols. Here, N_(DL) ^(SB) represents the number of resource blocks(RBs) in a downlink, N_(RB) ^(SC) represents the number of subcarriersconstituting one RB, and N_(symb) ^(DL) represents the number of OFDMsymbols in one downlink slot. The structure of this resource grid isshown in FIG. 3.

RBs are used to describe a mapping relationship between certain physicalchannels and resource elements. The RBs can be classified into physicalresource blocks (PRBs) and virtual resource blocks (VRBs), which meansthat a RB may be either one of a PRB or a VRB. A mapping relationshipbetween the VRBs and the PRBs can be described on a subframe basis. Inmore detail, it can be described in units of each of slots constitutingone subframe. Also, the mapping relationship between the VRBs and thePRBs can be described using a mapping relationship between indexes ofthe VRBs and indexes of PRBs. A detailed description of this will befurther given in embodiments of the present invention.

A PRB is defined by N_(symb) ^(DL) consecutive OFDM symbols in a timedomain and N_(SC) ^(RB) consecutive subcarriers in a frequency domain.One PRB is therefore composed of N_(symb) ^(DL) N_(SC) ^(RB) resourceelements. The PRBs are assigned numbers from 0 to N_(RB) ^(DL)−1 in thefrequency domain.

A VRB can have the same size as that of the PRB. There are two types ofVRBs defined, the first one being a localized type and the second onebeing a distributed type. For each VRB type, a pair of VRBs have asingle VRB index in common (may hereinafter be referred to as a ‘VRBnumber’) and are allocated over two slots of one subframe. In otherwords, N_(RB) ^(DL) VRBs belonging to a first one of two slotsconstituting one subframe are each assigned any one index of 0 to N_(RB)^(DL)−1, and N_(RB) ^(DL) VRBs belonging to a second one of the twoslots are likewise each assigned any one index of 0 to N_(RB) ^(DL)−1.

The index of a VRB corresponding to a specific virtual frequency band ofthe first slot has the same value as that of the index of a VRBcorresponding to the specific virtual frequency band of the second slot.That is, assuming that a VRB corresponding to an ith virtual frequencyband of the first slot is denoted by VRB1(i), a VRB corresponding to ajth virtual frequency band of the second slot is denoted by VRB2(j) andindex numbers of the VRB1(i) and VRB2(j) are denoted by index(VRB1(i))and index(VRB2(j)), respectively, a relationship ofindex(VRB1(k))=index(VRB2(k)) is established (see FIG. 4A).

Likewise, the index of a PRB corresponding to a specific frequency bandof the first slot has the same value as that of the index of a PRBcorresponding to the specific frequency band of the second slot. Thatis, assuming that a PRB corresponding to an ith frequency band of thefirst slot is denoted by PRB1(i), a PRB corresponding to a jth frequencyband of the second slot is denoted by PRB2(j) and index numbers of thePRB1(i) and PRB2(j) are denoted by index(PRB1(i)) and index(PRB2(j)),respectively, a relationship of index(PRB1(k))=index(PRB2(k)) isestablished (see FIG. 4B).

Some of the plurality of aforementioned VRBs are allocated as thelocalized type and the others are allocated as the distributed type.Hereinafter, the VRBs allocated as the localized type will be referredto as ‘localized virtual resource blocks (LVRBs)’ and the VRBs allocatedas the distributed type will be referred to as ‘distributed virtualresource blocks (DVRBs)’.

The localized VRBs (LVRBs) are directly mapped to PRBs and the indexesof the LVRBs correspond to the indexes of the PRBs. Also, LVRBs of indexi correspond to PRBs of index i. That is, an LVRB1 having the index icorresponds to a PRB1 having the index i, and an LVRB2 having the indexi corresponds to a PRB2 having the index i (see FIG. 5). In this case,it is assumed that the VRBs of FIG. 5 are all allocated as LVRBs.

The distributed VRBs (DVRBs) may not be directly mapped to PRBs. Thatis, the indexes of the DVRBs can be mapped to the PRBs after beingsubjected to a series of processes.

First, the order of a sequence of consecutive indexes of the DVRBs canbe interleaved by a block interleaver. Here, the sequence of consecutiveindexes means that the index number is sequentially incremented by onebeginning with 0. A sequence of indexes outputted from the interleaveris sequentially mapped to a sequence of consecutive indexes of PRB1s(see FIG. 6). It is assumed that the VRBs of FIG. 6 are all allocated asDVRBs. On the other hand, the sequence of indexes outputted from theinterleaver is cyclically shifted by a predetermined number and thecyclically shifted index sequence is sequentially mapped to a sequenceof consecutive indexes of PRB2s (see FIG. 7). It is assumed that theVRBs of FIG. 7 are all allocated as DVRBs. In this manner, PRB indexesand DVRB indexes can be mapped over two slots.

On the other hand, in the above processes, a sequence of consecutiveindexes of the DVRBs may be sequentially mapped to the sequence ofconsecutive indexes of the PRB1s without passing through theinterleaver. Also, the sequence of consecutive indexes of the DVRBs maybe cyclically shifted by the predetermined number without passingthrough the interleaver and the cyclically shifted index sequence may besequentially mapped to the sequence of consecutive indexes of the PRB2s.

According to the above-mentioned processes of mapping DVRBs to PRBs, aPRB1(i) and a PRB2(i) having the same index i can be mapped to aDVRB1(m) and a DVRB2(n) having different indexes m and n. For example,referring to FIGS. 6 and 7, a PRB1(1) and a PRB2(1) are mapped to aDVRB1(6) and a DVRB2(9) having different indexes. A frequency diversityeffect can be obtained based on the DVRB mapping scheme.

In the case where VRB(1)s, among the VRBs, are allocated as DVRBs as inFIG. 8, if the methods of FIGS. 6 and 7 are used, LVRBs cannot beassigned to a PRB2(6) and a PRB1(9) although VRBs have not been assignedyet to the PRB2(6) and PRB1(9). The reason is as follows: according tothe aforementioned LVRB mapping scheme, that LVRBs are mapped to thePRB2(6) and PRB1(9) means that LVRBs are also mapped to a PRB1(6) and aPRB2(9); however, the PRB1(6) and PRB2(9) have already been mapped bythe aforementioned VRB1(1) and VRB2(1). In this regard, it will beunderstood that the LVRB mapping may be restricted by the DVRB mappingresults. Therefore, there is a need to determine DVRB mapping rules inconsideration of the LVRB mapping.

In a broadband wireless mobile communication system using amulti-carrier, radio resources can be allocated to each terminal with aLVRB and/or DVRB scheme. The information indicating which scheme is usedcan be transmitted with a bitmap format. At this time, the allocation ofradio resources to each terminal can be carried out in units of one RB.In this case, resources can be allocated with a granularity of ‘1’ RB,but a large amount of bit overhead is required to transmit theallocation information with the bitmap format. Alternatively, an RBgroup (RBG) consisting of PRBs of k consecutive indexes (e.g., k=3) maybe defined and resources may be allocated with a granularity of 1′ RBG.In this case, the RB allocation is not sophisticatedly performed, butthere is an advantage that bit overhead is reduced.

In this case, LVRBs can be mapped to PRBs on an RBG basis. For example,PRBs having three consecutive indexes, a PRB1(i), PRB1(i+1), PRB1(i+2),PRB2(i), PRB2(i+1) and PRB2(i+2), may constitute one RBG, and LVRBs maybe mapped to this RBG in units of an RBG. However, in the case where oneor more of the PRB1(i), PRB1(i+1), PRB1(i+2), PRB2(i), PRB2(i+1) andPRB2(i+2) were previously mapped by DVRBs, this RBG cannot be mapped byLVRBs on an RBG basis. That is, the DVRB mapping rules may restrict theRBG-unit LVRB mapping.

As mentioned above, because the DVRB mapping rules may affect the LVRBmapping, there is a need to determine the DVRB mapping rules inconsideration of the LVRB mapping.

DISCLOSURE Technical Problem

An object of the present invention devised to solve the problem lies ona resource scheduling method for efficiently combining scheduling of anFSS scheme and scheduling of an FDS scheme.

Technical Solution

The object of the present invention can be achieved by providing, in awireless mobile communication system that supports a resource allocationscheme in which one resource block group (RBG) including consecutivephysical resource blocks is indicated by one bit, a resource blockmapping method for distributively mapping consecutively allocatedvirtual resource blocks to the physical resource blocks, the methodincluding: interleaving, using a block interleaver, indexes of thevirtual resource blocks determined from a resource indication value(RIV) indicating a start index number of the virtual resource blocks anda length of the virtual resource blocks; and sequentially mapping theinterleaved indexes to indexes of the physical resource blocks on afirst slot of one subframe, the subframe including the first slot and asecond slot, and sequentially mapping indexes obtained by cyclicallyshifting the interleaved indexes by a gap for the distribution to theindexes of the physical resource blocks on the second slot, wherein thegap is a multiple of a square of the number (M_(RBG)) of the consecutivephysical resource blocks constituting the RBG.

When a degree of the block interleaver is defined as the number (C=4) ofcolumns of the block interleaver, the number (R) of rows of the blockinterleaver may be given as in expression (1) and the number (N_(null))of nulls filled in the block interleaver may be given as in expression(2).

R=N _(interleaver) /C=┌N _(DVRB)/(C·M _(RBG))┐·M _(RBG)

N _(interleaver) =┌N _(DVRB)/(C·M _(RBG))┐·C·M _(RBG)  [Expression (1)]

where M_(RBG) is the number of the consecutive physical resource blocksconstituting the RBG, and N_(DVRB) is the number of the distributivelyallocated virtual resource blocks.

N _(null) =N _(interleaver) −N _(DVRB) =┌N _(DVRB)/(C·M _(RBG))┐·C·M_(RBG) −N _(DVRB)

N _(interleaver) =┌N _(DVRB)/(C·M _(RBG))┐·C·M _(RBG)  [Expression (2)]

where M_(RBG) is the number of the consecutive physical resource blocksconstituting the RBG, and N_(DVRB) is the number of the distributivelyallocated virtual resource blocks.

A degree of the block interleaver may be equal to a diversity order(N_(DivOrder)) determined by the distribution.

When an index d of one of the distributively allocated virtual resourceblocks is given, an index P_(1,d) of corresponding one of the physicalresource blocks on the first slot mapped to the index d may be given asin expression (3) and an index P_(2,d) of corresponding one of thephysical resource blocks on the second slot mapped to the index d may begiven as in expression (4). Here, R is the number of rows of the blockinterleaver, C is the number of columns of the block interleaver,N_(DVRB) is the number of resource blocks used for the distributivelyallocated virtual resource blocks, N_(null) is the number of nullsfilled in the block interleaver, and mod means a modulo operation.

$\begin{matrix}{p_{1,d} = \left\{ {{\begin{matrix}{p_{1,d}^{\prime},} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} = {0\mspace{14mu} {or}}} \\\begin{pmatrix}{d < {N_{DVRB} - {N_{null}\mspace{14mu} {and}}}} \\{{{mod}\left( {d,C} \right)} < 2}\end{pmatrix}\end{matrix} \\{{p_{1,d}^{\prime} - {N_{null}/2}},} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} \neq {0\mspace{14mu} {and}}} \\\begin{pmatrix}{d < {N_{DVRB} - {N_{null}\mspace{14mu} {and}}}} \\{{{mod}\left( {d,C} \right)} \geq 2}\end{pmatrix}\end{matrix}\end{matrix}\mspace{20mu} {where}\mspace{14mu} p_{1,d}^{\prime}} = {{{{{mod}\left( {d,C} \right)} \cdot R} + {\left\lfloor {d/C} \right\rfloor p_{1,d}}} = \left\{ {{\begin{matrix}{{p_{1,d}^{\prime} - R + {N_{null}/2}},} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} \neq {0\mspace{14mu} {and}}} \\\begin{pmatrix}{d{N_{DVRB} - {N_{null}\mspace{14mu} {and}}}} \\{{{mod}\left( {d,{C/2}} \right)} = 0}\end{pmatrix}\end{matrix} \\{{p_{1,d}^{\prime} - R},} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} \neq {0\mspace{14mu} {and}}} \\\begin{pmatrix}{d{N_{DVRB} - {N_{null}\mspace{14mu} {and}}}} \\{{{mod}\left( {d,{C/2}} \right)} = 1}\end{pmatrix}\end{matrix}\end{matrix}\mspace{20mu} {where}\mspace{14mu} p_{1,d}^{\prime}} = {{{{{mod}\left( {d,{C/2}} \right)} \cdot 2}R} + \left\lfloor {2{d/C}} \right\rfloor}} \right.}} \right.} & \left\lbrack {{Expression}\mspace{14mu} (3)} \right\rbrack\end{matrix}$P _(2,d)=mod(p _(1,d) +N _(DVRB)/2,N _(DVRB))  [Expression (4)]

Here, C may be equal to the degree of the block interleaver.

The index P_(1,d) may be p_(1,d)+N_(PRB)−N_(DVRB) when it is larger thanN_(DVRB)/2, and the index P_(2,d) may be P_(2,d)+N_(PRB)−N_(DVRB) whenit is larger than N_(DVRB)/2. Here, N_(PRB) is the number of physicalresource blocks in the system.

When the number (N_(DVRB)) of the virtual resource blocks is not amultiple of the degree of the block interleaver, the step ofinterleaving may include dividing the interleaver into groups of thenumber (N_(D)) of physical resource blocks to which one virtual resourceblock is mapped and uniformly distributing nulls to the divided groups.

The groups may correspond to rows of the block interleaver,respectively, when a degree of the block interleaver is the number ofthe rows of the block interleaver, and to columns of the blockinterleaver, respectively, when the degree of the block interleaver isthe number of the columns of the block interleaver.

In another aspect of the present invention, provided herein is, in awireless mobile communication system that supports a resource allocationscheme in which one resource block group (RBG) including consecutivephysical resource blocks is indicated by one bit, a resource blockmapping method for distributively mapping consecutively allocatedvirtual resource blocks to the physical resource blocks, the methodincluding: interleaving, using a block interleaver, indexes of thevirtual resource blocks determined from a resource indication value(RIV) indicating a start index number of the virtual resource blocks anda length of the virtual resource blocks; and sequentially mapping theinterleaved indexes to indexes of the physical resource blocks on afirst slot of one subframe, the subframe including the first slot and asecond slot, and sequentially mapping indexes obtained by cyclicallyshifting the interleaved indexes by a gap for the distribution to theindexes of the physical resource blocks on the second slot, wherein thegap (N_(gap)) for the distribution is given as in expression (5).

N _(gap)=round(N _(PRB)/2·M _(RBG) ²))·M _(RBG) ²  [Expression (5)]

where M_(RBG) is the number of the consecutive physical resource blocksconstituting the RBG, and N_(PRB) is the number of physical resourceblocks in the system.

When nulls are allowed to be inputted to the block interleaver, thenumber (N_(DVRB)) of the distributively allocated virtual resourceblocks may be given as in expression (6).

N _(DVRB)=min(N _(PRB) −N _(gap) ,N _(gap))·2  [Expression (6)]

When an index d of one of the distributively allocated virtual resourceblocks is given, an index P_(1,d) of corresponding one of the physicalresource blocks on the first slot mapped to the index d may bep_(1,d)+N_(PRB)−N_(DVRB) when it is larger than N_(DVRB/)2, and an indexP_(2,d) of corresponding one of the physical resource blocks on thesecond slot mapped to the index d may be p_(2,d)+N_(PRB)−N_(DVRB) whenit is larger than N_(DVRB/)2, wherein N_(DVRB) is the number of resourceblocks used for the distributively allocated virtual resource blocks.

In another aspect of the present invention, provided herein is, in awireless mobile communication system that supports a resource allocationscheme in which one resource block group (RBG) including consecutivephysical resource blocks is indicated by one bit, a resource blockmapping method for distributively mapping consecutively allocatedvirtual resource blocks to the physical resource blocks, the methodincluding: detecting a resource indication value (RIV) indicating astart index number of the virtual resource blocks and a length of thevirtual resource blocks and determining indexes of the virtual resourceblocks from the detected resource indication value; and interleaving thedetermined indexes of the virtual resource blocks using a blockinterleaver and distributively mapping the virtual resource blocks tothe physical resource blocks, wherein a degree of the block interleaveris equal to a diversity order (N_(DivOrder)) determined by thedistribution.

In another aspect of the present invention, provided herein is, in awireless mobile communication system that supports a resource allocationscheme in which one resource block group (RBG) including consecutivephysical resource blocks is indicated by one bit, a resource blockmapping method for distributively mapping consecutively allocatedvirtual resource blocks to the physical resource blocks, the methodincluding: determining indexes of the virtual resource blocks from aresource indication value (RIV) indicating a start index number of thevirtual resource blocks and a length of the virtual resource blocks; andinterleaving the determined indexes of the virtual resource blocks usinga block interleaver and distributively mapping the virtual resourceblocks to the physical resource blocks, wherein, when the number(N_(DVRB)) of the virtual resource blocks is not a multiple of a degreeof the block interleaver, the step of mapping includes dividing theinterleaver into groups of the number (N_(D)) of physical resourceblocks to which one virtual resource block is mapped and uniformlydistributing nulls to the divided groups.

The groups may correspond to rows of the block interleaver,respectively, when a degree of the block interleaver is the number ofthe rows of the block interleaver, and to columns of the blockinterleaver, respectively, when the degree of the block interleaver isthe number of the columns of the block interleaver.

The control information may be a DCI transmitted over a PDCCH.

The gap may be a function of a system bandwidth.

When an index p of one of the physical resource blocks is given, aninterleaved index d_(p1) mapped to the index p may be given as inexpression (7) or expression (8), and a cyclically shifted index d_(p2)mapped to the index p may be given as in expression (9) or expression(10). Here, R is the number of rows of the block interleaver, C is thenumber of columns of the block interleaver, N_(DVRB) is the number ofresource blocks used for the distributively allocated virtual resourceblocks, and mod means a modulo operation.

$\begin{matrix}{\mspace{20mu} {{d_{p_{1}} = {{{{mod}\left( {p^{\prime},R} \right)} \cdot C} + \left\lfloor {p^{\prime}/R} \right\rfloor}}\mspace{20mu} {where}{p^{\prime} = \left\{ \begin{matrix}{{p + 1},} & \begin{matrix}{{{when}\mspace{14mu} {{mod}\left( {N_{DVRB},C} \right)}} \neq {0\mspace{14mu} {and}}} \\{p \geq {{2R} - {1\mspace{14mu} {and}\mspace{14mu} p}} \neq {{3R} - 2}}\end{matrix} \\{{{2R} - 1},} & \begin{matrix}{{{when}\mspace{14mu} {{mod}\left( {N_{DVRB},C} \right)}} \neq {0\mspace{14mu} {and}}} \\{p = {{3R} - 2}}\end{matrix} \\{p,} & {{{when}\mspace{14mu} {{mod}\left( {N_{DVRB},C} \right)}} = {{0\mspace{14mu} {or}\mspace{14mu} p} < {{2R} - 1}}}\end{matrix} \right.}}} & \left\lbrack {{Expression}\mspace{14mu} (7)} \right\rbrack\end{matrix}$

$\begin{matrix}{\mspace{20mu} {{d_{p_{1}} = {{{{mod}\left( {p^{\prime},R} \right)} \cdot C} + \left\lfloor {p^{\prime}/R} \right\rfloor}}\mspace{20mu} {where}{p^{\prime} = \left\{ \begin{matrix}{{p + 1},} & \begin{matrix}{{{when}\mspace{14mu} {{mod}\left( {N_{DVRB},C} \right)}} \neq {0\mspace{14mu} {and}}} \\{p \geq {{2R} - {1\mspace{14mu} {and}\mspace{14mu} p}} \neq {{3R} - 2}}\end{matrix} \\{{{2R} - 1},} & \begin{matrix}{{{when}\mspace{14mu} {{mod}\left( {N_{DVRB},C} \right)}} \neq {0\mspace{14mu} {and}}} \\{p = {{3R} - 2}}\end{matrix} \\{p,} & {{{when}\mspace{14mu} {{mod}\left( {N_{DVRB},C} \right)}} = {{0\mspace{14mu} {or}\mspace{14mu} p} < {{2R} - 1}}}\end{matrix} \right.}}} & \left\lbrack {{Expression}\mspace{14mu} (8)} \right\rbrack\end{matrix}$

$\begin{matrix}{\mspace{20mu} {{d_{p_{2}} = {{{{mod}\left( {p^{''},R} \right)} \cdot C} + \left\lfloor {p^{''}/R} \right\rfloor}}\mspace{20mu} {where}{p^{''} = \left\{ {{\begin{matrix}{{p^{\prime\prime\prime} + 1},} & \begin{matrix}{{{when}\mspace{14mu} {{mod}\left( {N_{{DVR}\; B},C} \right)}} \neq {0\mspace{14mu} {and}}} \\{p^{\prime\prime\prime} \geq {{2R} - {1\mspace{14mu} {and}\mspace{14mu} p^{\prime\prime\prime}}} \neq {{3R} - 2}}\end{matrix} \\{{{2R} - 1},} & \begin{matrix}{{{when}\mspace{14mu} {{mod}\left( {N_{DVRB},C} \right)}} \neq {0\mspace{14mu} {and}}} \\{p^{\prime\prime\prime} = {{3R} - 2}}\end{matrix} \\{p^{\prime\prime\prime},} & \begin{matrix}{{{when}\mspace{14mu} {{mod}\left( {N_{DVRB},C} \right)}} = {0\mspace{14mu} {or}}} \\{p^{\prime\prime\prime} < {{2R} - 1}}\end{matrix}\end{matrix}\mspace{20mu} {where}\mspace{14mu} p^{\prime\prime\prime}} = {{mod}\left( {{p + {N_{DVRB}/2}},N_{DVRB}} \right)}} \right.}}} & \left\lbrack {{Expression}\mspace{14mu} (9)} \right\rbrack\end{matrix}$

$\begin{matrix}{d_{p_{2\;}} = \left\{ \begin{matrix}{{d_{p_{1}} - 2},} & {{{when}\mspace{14mu} {{mod}\left( {d_{p_{1}},C} \right)}} \geq 2} \\{{d_{p_{1}} + 2},} & \begin{matrix}{{{when}\mspace{14mu} {{mod}\left( {d_{p_{1}},C} \right)}} < {2\mspace{14mu} {and}}} \\{d_{p_{1}} \neq {N_{DVRB} - {2\mspace{14mu} {and}\mspace{14mu} d_{p_{1}}}} \neq {N_{DVRB} - 1}}\end{matrix} \\{{N_{DVRB} - 1},} & \begin{matrix}{{{when}\mspace{14mu} {{mod}\left( {d_{p_{1}},C} \right)}} < {2\mspace{14mu} {and}}} \\{d_{p_{1\;}} = {N_{DVRB} - 2}}\end{matrix} \\{{N_{DVRB} - 2},} & \begin{matrix}{{{when}\mspace{14mu} {{mod}\left( {d_{p_{1}},C} \right)}} < {2\mspace{14mu} {and}}} \\{d_{p_{1\;}} = {N_{DVRB} - 1}}\end{matrix}\end{matrix} \right.} & \left\lbrack {{Expression}\mspace{14mu} (10)} \right\rbrack\end{matrix}$

The diversity order (N_(DivOrder)) may be a multiple of the number(N_(D)) of physical resource blocks to which one virtual resource blockis mapped.

The gap may be 0 when the number of the virtual resource blocks islarger than or equal to a predetermined threshold value (M_(th)).

The resource block mapping method may further include receivinginformation about the gap, the gap being determined by the received gapinformation.

In another aspect of the present invention, provided herein is, in awireless mobile communication system that supports an RBG resourceallocation scheme and a subset resource allocation scheme, a resourceblock mapping method for distributively mapping consecutively allocatedvirtual resource blocks to physical resource blocks, the methodincluding: receiving control information including resource blockallocation information indicating distributed allocation of the virtualresource blocks, and indexes of the virtual resource blocks; andinterleaving the indexes of the virtual resource blocks using a blockinterleaver, wherein the step of interleaving includes, until theindexes of the virtual resource blocks are mapped to all indexes ofphysical resource blocks belonging to any one of a plurality of RBGsubsets, preventing the indexes of the virtual resource blocks frombeing mapped to indexes of physical resource blocks belonging to adifferent one of the RBG subsets.

The resource block mapping method may further include sequentiallymapping the interleaved indexes to indexes of the physical resourceblocks on a first slot of one subframe, the subframe including the firstslot and a second slot, and sequentially mapping indexes obtained bycyclically shifting the interleaved indexes by a gap for thedistribution to the indexes of the physical resource blocks on thesecond slot, wherein the gap for the distribution is determined suchthat the virtual resource blocks mapped on the first slot and thevirtual resource blocks mapped on the second slot are included in thesame subset.

The number (N_(DVRB)) of the virtual resource blocks may be a multipleof a diversity order (N_(DivOrder)) determined by the distribution.

The number (N_(DVRB)) of the virtual resource blocks may be a multipleof the number M_(RBG) of the consecutive physical resource blocksconstituting the RBG.

The number (N_(DVRB)) of the virtual resource blocks may be a multipleof a value obtained by multiplying the number M_(RBG) of the consecutivephysical resource blocks constituting the RBG by the number (N_(D)) ofphysical resource blocks to which one virtual resource block is mapped.

The number (N_(DVRB)) of the virtual resource blocks may be a multipleof a value obtained by multiplying the square (M_(RBG) ²) of the numberof the consecutive physical resource blocks constituting the RBG by thenumber (N_(D)) of physical resource blocks to which one virtual resourceblock is mapped.

The number N_(DVRB) of the virtual resource blocks may be a commonmultiple of a value obtained by multiplying the number (M_(RBG)) of theconsecutive physical resource blocks constituting the RBG by the number(N_(D)) of physical resource blocks to which one virtual resource blockis mapped and a degree (D) of the block interleaver.

The degree (D) of the block interleaver may be a multiple of the number(N_(D)) of physical resource blocks to which one virtual resource blockis mapped.

The number N_(DVRB) of the virtual resource blocks may be a commonmultiple of a value obtained by multiplying a square (M_(RBG) ²) of thenumber of the consecutive physical resource blocks constituting the RBGby the number (N_(D)) of physical resource blocks to which one virtualresource block is mapped and a degree (D) of the block interleaver.

The degree (D) of the block interleaver may be a multiple of the number(N_(D)) of physical resource blocks to which one virtual resource blockis mapped.

The number N_(DVRB) of the virtual resource blocks may be a commonmultiple of a value obtained by multiplying a degree (D) of the blockinterleaver by a square (M_(RBG) ²) of the number of the consecutivephysical resource blocks constituting the RBG and a value obtained bymultiplying the number (N_(D)) of physical resource blocks to which onevirtual resource block is mapped by the square (M_(RBG) ²) of the numberof the consecutive physical resource blocks constituting the RBG.

The degree (D) of the block interleaver may be a multiple of the number(N_(D)) of physical resource blocks to which one virtual resource blockis mapped.

The aforementioned various aspects of the present invention are allapplicable to a base station and/or mobile station. In the case wherethe aforementioned aspects of the present invention are applied to themobile station, the resource block mapping method may further includereceiving the resource indication value (RIV) from the mobile station ofthe wireless mobile communication system, prior to the step ofinterleaving or the step of determining the indexes of the virtualresource blocks.

Advantageous Effects

According to the present invention, it is possible to efficientlycombine scheduling of an FSS scheme and scheduling of an FDS scheme andsimply implement a scheduling information transfer method.

DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention, illustrate embodiments of the inventionand together with the description serve to explain the principle of theinvention.

In the drawings:

FIG. 1 is a view showing an example of a radio frame structureapplicable to FDD.

FIG. 2 is a view showing an example of a radio frame structureapplicable to TDD.

FIG. 3 is a view showing an example of a resource grid structureconstituting a 3GPP transmission slot.

FIG. 4A is a view showing an example of the structure of VRBs in onesubframe.

FIG. 4B is a view showing an example of the structure of PRBs in onesubframe.

FIG. 5 is a view illustrating an example of a method for mapping LVRBsto PRBs.

FIG. 6 is a view illustrating an example of a method for mapping DVRBsin a first slot to PRBs.

FIG. 7 is a view illustrating an example of a method for mapping DVRBsin a second slot to PRBs.

FIG. 8 is a view illustrating an example of a method for mapping DVRBsto PRBs.

FIG. 9 is a view illustrating an example of a method for mapping DVRBsand LVRBs to PRBs.

FIG. 10 is a view illustrating an example of a method for allocatingresource blocks by a compact scheme.

FIG. 11 is a view illustrating an example of a method for mapping twoDVRBs having consecutive indexes to a plurality of contiguous PRBs.

FIG. 12 is a view illustrating an example of a method for mapping twoDVRBs having consecutive indexes to a plurality of spaced PRBs.

FIG. 13 is a view illustrating an example of a method for mapping fourDVRBs having consecutive indexes to a plurality of spaced PRBs.

FIG. 14 is a view illustrating an example of a resource block mappingmethod in the case where Gap=0, according to one embodiment of thepresent invention.

FIG. 15 is a view illustrating a bitmap configuration.

FIG. 16 is a view illustrating an example of a method for mapping basedon a combination of a bitmap scheme and a compact scheme.

FIGS. 17 and 18 are views illustrating a DVRB mapping method accordingto one embodiment of the present invention.

FIG. 19 is a view illustrating an example of a method for interleavingDVRB indexes.

FIGS. 20A and 20B are views illustrating an operation of a generalinterleaver when the number of resource blocks used in an interleavingoperation is not a multiple of a diversity order.

FIGS. 21A and 21B are views illustrating a method for inserting nullswhen the number of resource blocks used in an interleaving operation isnot a multiple of a diversity order, in accordance with one embodimentof the present invention.

FIG. 22 is a view illustrating a method for mapping interleaved DVRBindexes with Gap=0 in accordance with one embodiment of the presentinvention.

FIG. 23 is a view illustrating an example of a method for mapping DVRBindexes, using different gaps for different terminals.

FIG. 24 is a view for explaining the relation between DVRB and PRBindexes.

FIG. 25A is a view for explaining the relation between DVRB and PRBindexes.

FIG. 25B is a view illustrating a general method for inserting nulls inan interleaver.

FIGS. 25C and 25D are views illustrating examples of a method forinserting nulls in an interleaver in one embodiment of the presentinvention, respectively.

FIGS. 26 and 27 are views illustrating examples of a method using acombination of the bitmap scheme using the RBG scheme and subset schemeand the compact scheme, respectively.

FIG. 28 is a view illustrating the case in which the number of DVRBs isset to a multiple of the number of physical resource blocks (PRBs), towhich one virtual resource block (VRB) is mapped, N_(D), and the numberof consecutive physical resource blocks constituting an RBG, M_(RBG), inaccordance with one embodiment of the present invention.

FIG. 29 is a view illustrating the case in which DVRB indexes areinterleaved in accordance with the method of FIG. 28.

FIG. 30 is a view illustrating an example wherein mapping is performedunder the condition in which the degree of a block interleaver is set tothe number of columns of the block interleaver, namely, C, and C is setto a diversity order, in accordance with one embodiment of the presentinvention.

FIG. 31 is a view illustrating an example of a mapping method accordingto one embodiment of the present invention when the number of PRBs andthe number of DVRBs are different from each other.

FIGS. 32 and 33 are views illustrating examples of a mapping methodcapable of increasing the number of DVRBs, using a given gap, inaccordance with one embodiment of the present invention.

MODE FOR INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention with reference to the accompanying drawings. Thedetailed description, which will be given below with reference to theaccompanying drawings, is intended to explain exemplary embodiments ofthe present invention, rather than to show the only embodiments that canbe implemented according to the invention. The following detaileddescription includes specific details in order to provide a thoroughunderstanding of the present invention. However, it will be apparent tothose skilled in the art that the present invention may be practicedwithout such specific details. For example, the following descriptionwill be given centering around specific terms, but the present inventionis not limited thereto and any other terms may be used to represent thesame meanings. Also, wherever possible, the same reference numbers willbe used throughout the drawings to refer to the same or like parts.

In the case where a subframe consists of a first slot and a second slot,index(PRB1(i)) represents an index of a PRB of an ith frequency band ofthe first slot, index(PRB2(j)) represents an index of a PRB of a jthfrequency band of the second slot, and a relationship ofindex(PRB1(k))=index(PRB2(k)) is established, as stated previously.Also, index(VRB1(i)) represents an index of a VRB of an ith virtualfrequency band of the first slot, index(VRB2(j)) represents an index ofa VRB of a jth virtual frequency band of the second slot, and arelationship of index(VRB1(k))=index(VRB2(k)) is established. At thistime, VRB1s are mapped to PRB1s, and VRB2s are mapped to PRB2s. Also,VRBs are classified into DVRBs and LVRBs.

The rules for mapping LVRB1s to PRB1s and the rules for mapping LVRB2sto PRB2s are the same. However, the rules for mapping DVRB1s to PRB1sand the rules for mapping DVRB2s to PRB2s are different. That is, DVRBsare ‘divided’ and mapped to PRBs.

In the 3GPP, one RB is defined in units of one slot. However, in thedetailed description of the invention, one RB is defined in units of onesubframe, and this RB is divided into N_(D) sub-RBs on a time axis, sothat the DVRB mapping rules are generalized and described. For example,in the case where N_(D)=2, a PRB defined in units of one subframe isdivided into a first sub-PRB and a second sub-PRB, and a VRB defined inunits of one subframe is divided into a first sub-VRB and a secondsub-VRB.

In this case, the first sub-PRB corresponds to the aforementioned PRB1,and the second sub-PRB corresponds to the aforementioned PRB2. Also, thefirst sub-VRB corresponds to the aforementioned VRB1, and the secondsub-VRB corresponds to the aforementioned VRB2. Also, in both thedetailed description of the invention and the 3GPP, the DVRB mappingrules for obtaining a frequency effect is described on the basis of onesubframe. Therefore, it will be understood that all embodiments of thedetailed description of the invention are concepts including an RBmapping method in the 3GPP.

Hereinafter, terms used in the detailed description of this applicationare defined as follows.

A ‘resource element (RE)’ represents a smallest frequency-time unit inwhich data or a modulated symbol of a control channel is mapped.Provided that a signal is transmitted in one OFDM symbol over Msubcarriers and N OFDM symbols are transmitted in one subframe, M×N REsare present in one subframe.

A ‘physical resource block (PRB)’ represents a unit frequency-timeresource for data transmission. In general, one PRB consists of aplurality of consecutive REs in a frequency-time domain, and a pluralityof PRBs are defined in one subframe.

A ‘virtual resource block (VRB)’ represents a virtual unit resource fordata transmission. In general, the number of REs included in one VRB isequal to that of REs included in one PRB, and, when data is transmitted,one VRB can be mapped to one PRB or some areas of a plurality of PRBs.

A ‘localized virtual resource block (LVRB)’ is one type of the VRB. OneLVRB is mapped to one PRB. A PRB mapped to one LVRB is different from aPRB mapped to another LVRB.

A ‘distributed virtual resource block (DVRB)’ is another type of theVRB. One DVRB is mapped to a plurality of PRBs in a distributed manner.

‘N_(D)’=‘N_(d)’ represents the number of PRBs to which one DVRB ismapped. FIG. 9 illustrates an example of a method for mapping DVRBs andLVRBs to PRBs. In FIG. 9, N_(D)=3. An arbitrary DVRB can be divided intothree parts and the divided parts can be mapped to different PRBs,respectively. At this time, the remaining part of each PRB, not mappedby the arbitrary DVRB, is mapped by a divided part of a different DVRB.

‘N_(PRB)’ represents the number of PRBs in a system. In the case wherethe band of the system is divided, N_(PRB) may be the number of PRBs inthe divided part.

‘N_(LVRB)’ represents the number of LVRBs available in the system.

‘N_(DVRB)’ represents the number of DVRBs available in the system.

‘N_(LVRB) _(—) _(UE)’ represents the maximum number of LVRBs allocableto one user equipment (UE).

‘N_(DVRB) _(—) _(UE)’ represents the maximum number of DVRBs allocableto one UE.

‘N_(subset)’ represents the number of subsets.

‘N_(DivOrder)’ represents a diversity order required in the system.Here, the diversity order is defined by the number of RBs which are notadjacent to each other.

Here, the “number of RBs” means the number of RBs divided on a frequencyaxis. That is, even in the case where RBs can be divided by time slotsconstituting a subframe, the “number of RBs” means the number of RBsdivided on the frequency axis of the same slot.

FIG. 9 shows an example of definitions of LVRBs and DVRBs.

As can be seen from FIG. 9, each RE of one LVRB is one-to-one mapped toeach RE of one PRB. For example, one LVRB is mapped to a PRB0 (901). Incontrast, one DVRB is divided into three parts and the divided parts aremapped to different PRBs, respectively. For example, a DVRB0 is dividedinto three parts and the divided parts are mapped to a PRB1, PRB4 andPRB6, respectively. Likewise, a DVRB1 and a DVRB2 are each divided intothree parts and the divided parts are mapped to the remaining resourcesof the PRB1, PRB4 and PRB6. Although each DVRB is divided into threeparts in this example, the present invention is not limited thereto. Forexample, each DVRB may be divided into two parts.

Downlink data transmission from a base station to a specific terminal oruplink data transmission from the specific terminal to the base stationis made through one or more VRBs in one subframe. When the base stationtransmits data to the specific terminal, it has to notify the terminalof which one of the VRBs is used for data transmission. Also, in orderto enable the specific terminal to transmit data, the base station hasto notify the terminal of which one of the VRBs is allowed to use fordata transmission.

Data transmission schemes can be broadly classified into a frequencydiversity scheduling (FDS) scheme and a frequency selective scheduling(FSS) scheme. The FDS scheme is a scheme that obtains a receptionperformance gain through frequency diversity, and the FSS scheme is ascheme that obtains a reception performance gain through frequencyselective scheduling.

In the FDS scheme, a transmission stage transmits one data packet oversubcarriers widely distributed in a system frequency domain so thatsymbols in the data packet can experience various radio channel fadings.Therefore, an improvement in reception performance is obtained bypreventing the entire data packet from being subject to unfavorablefading. In contrast, in the FSS scheme, an improvement in receptionperformance is obtained by transmitting the data packet over one or moreconsecutive frequency areas in the system frequency domain which are ina favorable fading state. In a cellular OFDM wireless packetcommunication system, a plurality of terminals are present in one cell.At this time, because the radio channel conditions of the respectiveterminals have different characteristics, it is necessary to performdata transmission of the FDS scheme with respect to a certain terminaland data transmission of the FSS scheme with respect to a differentterminal even within one subframe. As a result, a detailed FDStransmission scheme and a detailed FSS transmission scheme must bedesigned such that the two schemes can be efficiently multiplexed withinone subframe. On the other hand, in the FSS scheme, a gain can beobtained by selectively using a band favorable to a UE among allavailable bands. In contrast, in the FDS scheme, an evaluation is notmade as to whether a specific band is good or bad, and, as long as afrequency separation capable of adequately obtaining a diversity ismaintained, there is no need to select and transmit a specific frequencyband. Accordingly, it is advantageous to an improvement in entire systemperformance to perform the frequency selective scheduling of the FSSscheme preferentially when scheduling.

In the FSS scheme, because data is transmitted using subcarriersconsecutively contiguous in the frequency domain, it is preferable thatthe data is transmitted using LVRBs. At this time, provided that N_(PRB)PRBs are present in one subframe and a maximum of N_(LVRB) LVRBs areavailable within the system, the base station can transmit bitmapinformation of N_(LVRB) bits to each terminal to notify the terminal ofwhich one of the LVRBs through which downlink data will be transmittedor which one of the LVRBs through which uplink data can be transmitted.That is, each bit of the N_(LVRB)-bit bitmap information, which istransmitted to each terminal as scheduling information, indicateswhether data will or can be transmitted through an LVRB corresponding tothis bit, among the N_(LVRB) LVRBs. This scheme is disadvantageous inthat, when the number N_(LVRB) becomes larger, the number of bits to betransmitted to each terminal becomes larger in proportion thereto.

On the other hand, provided that a terminal can be allocated only oneset of contiguous RBs, information of the allocated RBs can be expressedby a start point of the RBs and the number thereof. This scheme isreferred to as a ‘compact scheme’ in this document.

FIG. 10 illustrates an example of a method for allocating resourceblocks by the compact scheme.

In this case, as shown in FIG. 10, the length of available RBs isdifferent depending on respective start points, and the number ofcombinations of RB allocation is N_(LVRB)(N_(LVRB)+1)/2 in the end.Accordingly, the number of bits required for the combinations isceiling(log₂(N_(LVRB)(N_(LVRB)+1)/2)). Here, ceiling(x) means rounding“x” up to a nearest integer. This method is advantageous over the bitmapscheme in that the number of bits does not so significantly increasewith the increase in the number N_(LVRB).

On the other hand, for a method for notifying a user equipment (UE) ofDVRB allocation, it is necessary to previously promise the positions ofrespective divided parts of DVRBs distributively transmitted for adiversity gain. Alternatively, additional information may be required todirectly notify the positions. Preferably, provided that the number ofbits for signaling for the DVRBs is set to be equal to the number ofbits in LVRB transmission of the above-stated compact scheme, it ispossible to simplify a signaling bit format in a downlink. As a result,there are advantages that the same channel coding can be used, etc.

Here, in the case where one UE is allocated a plurality of DVRBs, thisUE is notified of a DVRB index of a start point of the DVRBs, a length(=the number of the allocated DVRBs), and a relative position differencebetween divided parts of each DVRB (e.g., a gap between the dividedparts).

FIG. 11 illustrates an example of a method for mapping two DVRBs havingconsecutive indexes to a plurality of contiguous PRBs.

As shown in FIG. 11, in the case where a plurality of DVRBs havingconsecutive indexes are mapped to a plurality of contiguous PRBs, firstdivided parts 1101 and 1102 and second divided parts 1103 and 1104 arespaced part from each other by a gap 1105, while divided parts belongingto each of the upper divided parts and lower divided parts arecontiguous to each other, so that the diversity order becomes 2.

FIG. 12 illustrates an example of a method for mapping two DVRBs havingconsecutive indexes to a plurality of spaced PRBs. In this application,‘spaced PRBs’ means that the PRBs are not adjacent to each other.

In the method of FIG. 12, when allowing DVRBs to correspond to PRBs,consecutive DVRB indexes can be allowed to be distributed, notcorrespond to contiguous PRBs. For example, a DVRB index ‘0’ and a DVRBindex ‘1’ are not arranged contiguous to each other. In other words, inFIG. 12, DVRB indexes are arranged in the order of 0, 8, 16, 4, 12, 20,. . . , and this arrangement can be obtained by inputting theconsecutive indexes shown in FIG. 11 to, for example, a blockinterleaver. In this case, it is possible to obtain distribution withineach of divided parts 1201 and 1202, as well as distribution by a gap1203. Therefore, when a UE is allocated two DVRBs as shown in FIG. 12,the diversity order increases to 4, resulting in an advantage that thediversity gain can be obtained still more.

At this time, the value of the gap indicative of the relative positiondifference between the divided parts can be expressed in two ways.Firstly, the gap value can be expressed by a difference between DVRBindexes. Secondly, the gap value can be expressed by a differencebetween indexes of PRBs to which a DVRB is mapped. In the case of FIG.12, Gap=1 in the first way, while Gap=3 in the second way. FIG. 12 showsthe latter case 1203. Meanwhile, if the total number of RBs of thesystem is changed, the DVRB index arrangement may be changedaccordingly. In this case, the use of the second way has the advantageof grasping a physical distance between the divided parts.

FIG. 13 illustrates the case where one UE is allocated four DVRBs underthe same rules as those of FIG. 12.

As can be seen from FIG. 13, the diversity order increases to 7.However, as the diversity order increases, the diversity gain converges.The results of existing studies represent that the increase in thediversity gain is insignificant when the diversity order is about 4 ormore. The un-mapped parts of PRBs 1301, 1302, 1303, 1304, and 1305 canbe allocated and mapped for other UE which uses DVRBs, however, theun-mapped parts cannot be allocated and mapped for another UE which usesLVRBs. Therefore, when there are no other UEs using DVRBs, there is adisadvantage that the un-mapped parts of the PRBs 1301, 1302, 1303, 1304and 1305 cannot help being left empty, not used. In addition, thedistributed arrangement of DVRBs breaks consecutiveness of availablePRBs, resulting in a restriction in allocating consecutive LVRBs.

As a result, there is a need for a method to limit the diversity orderto a proper level to carry out the distributed allocation.

A first embodiment and second embodiment of the present invention aredirected to methods for setting a relative distance between dividedparts of a DVRB mapped to PRBs to 0. In these embodiments, in a schemefor mapping consecutive DVRB indexes to spaced PRBs, when a plurality ofDVRBs are allocated to one UE, respective divided parts of each of theDVRBs can be distributively allocated to different PRBs, thereby raisingthe diversity order. Alternatively, under the same conditions, therespective divided parts of each DVRB may be allocated to the same PRB,not distributively allocated to different PRBs. In this case, it ispossible to reduce the number of PRBs to which DVRBs are distributivelyallocated, thus limiting the diversity order.

Embodiment 1

This embodiment is directed to a method for switching divided parts to adistributed/non-distributed mode by setting a reference value for thenumber of DVRBs allocated to one UE. Here, the ‘distributed mode’ refersto a mode where the gap between divided DVRB parts is not 0, and the‘non-distributed mode’ refers to a mode where the gap between dividedDVRB parts is 0.

Assume that the number of DVRBs allocated to one UE is M. When M issmaller than a specific reference value (=M_(th)), divided parts of eachDVRB are distributively allocated, thereby raising the diversity order.

Conversely, when M is larger than or equal to the reference value(=M_(th)), the divided parts are allocated to the same PRB, notdistributively allocated. This allocation of the divided parts to thesame PRB can reduce the number of PRBs to which DVRBs are distributivelymapped, thus limiting the diversity order.

That is, in the case where M is larger than or equal to the referencevalue M_(th), a gap, which is a relative distance between divided partsof each DVRB mapped to PRBs, is set to 0.

For example, if the number of DVRBs is 2 under the condition thatM_(th)=3, divided parts of each DVRB can be distributively mapped asshown in FIG. 12. In contrast, if the number of DVRBs is 4 under thecondition that M_(th)=3, a gap is set to 0 so that divided parts of eachDVRB can be mapped to the same PRB.

FIG. 14 illustrates an example of a resource block mapping method in thecase where Gap=0, according to the embodiment 1.

Embodiment 2

This embodiment is directed to a method for switching divided parts to adistributed/non-distributed mode using a control signal. Here, the‘distributed mode’ refers to a mode where the gap between divided DVRBparts is not 0, and the ‘non-distributed mode’ refers to a mode wherethe gap between divided DVRB parts is 0.

The embodiment 2 is a modified version of the embodiment 1. In theembodiment 2, M_(th) is not set, and, as needed, a control signal istransmitted and received to switch divided parts to thedistributed/non-distributed mode. In response to the transmitted andreceived control signal, divided DVRB parts can be distributed to raisethe diversity order or be mapped to the same PRB to lower the diversityorder.

For example, the control signal may be defined to indicate the value ofa gap, which is a relative distance between divided parts of each DVRBmapped to PRBs. That is, the control signal may be defined to indicatethe gap value itself.

For example, in the case where the control signal indicates that Gap=3,divided DVRB parts are distributively mapped as shown in FIG. 12 or 13.Also, in the case where the control signal indicates that Gap=0, dividedDVRB parts are mapped to the same PRB as shown in FIG. 14.

As stated previously, in order to freely schedule the number N_(PRB) ofPRBs in the system on a PRB basis, it is necessary to transmit anN_(PRB)-bit bitmap to each UE to be scheduled. When the number N_(PRB)of PRBs in the system is large, overhead of control information isincreased for transmission of the N_(PRB)-bit bitmap. Therefore,consideration can be given to a method for scaling down a schedulingunit or dividing the entire band and then performing transmission indifferent scheduling units in only some bands.

In the 3GPP LTE, a bitmap configuration scheme has been proposed inconsideration of overhead when the bitmap is transmitted as statedabove.

FIG. 15 illustrates a bitmap configuration.

A signal for resource allocation consists of a header 1501 and a bitmap1502. The header 1501 indicates the structure of the bitmap 1502 beingtransmitted, namely, a bitmap scheme, by indicating a signaling scheme.

The bitmap scheme is classified into two types, an RBG scheme and asubset scheme.

In the RBG scheme, RBs are grouped into a plurality of groups. RBs aremapped in units of one group. That is, a plurality of RBs constitutingone group have association of mapping. When the group size is larger, itis difficult to minutely perform resource allocation, but it is possibleto reduce the number of bits of a bitmap. Referring to FIG. 15, becauseN_(PRB)=32, a bitmap of a total of 32 bits is required for one RB-unitresource allocation. However, provided that three RBs are grouped (P=3)and resources are allocated on an RB group (RBG) basis, all RBs can bedivided into a total of eleven groups. As a result, only a bitmap of 11bits is required, thereby significantly reducing the amount of controlinformation. In contrast, in the case where resources are allocated onthis RBG basis, they cannot be allocated in units of one RB, so thatthey cannot be minutely allocated.

In order to make up for it, the subset scheme is used. In this scheme, aplurality of RBGs are set as one subset, and resources are allocated onan RB basis within each subset. In order to use the 11-bit bitmap in theabove-stated RBG scheme of FIG. 15, it is possible to configure ‘3’subsets (subset 1, subset 2 and subset 3). Here, ‘3’ is the number ofRBs constituting each RBG stated above. As a result,N_(RB)/P=ceiling(32/3)=11, so that RBs in each subset can be allocatedon the RB basis with 11 bits. Here, the header information 1501 isrequired to indicate which one of the RBG scheme and subset scheme isused for the bitmap and which subset is used if the subset scheme isused.

Provided that the header information 1501 just indicates which one ofthe RBG scheme and subset scheme is used and some bits of the bitmapused for the RBGs are used to indicate the subset type, all the RBs inall the subsets may not be utilized. For example, referring to FIG. 15,because a total of three subsets are set, a 2-bit subset indicator 1503is required to identify the subsets. At this time, a total of 12 RBs areassigned to the subset 1 1504 or 1505, and only 9 bits are left in thebitmap of a total of 11 bits if 2 bits of the subset indicator 1503 areexcepted from the bitmap. It is not possible to individually indicateall of the twelve RBs with 9 bits. In order to solve this, one bit ofthe RBG bitmap can be assigned as a shift indicator 1506 so that it canbe used to shift the position of an RB indicated by the subset bitmap.For example, in the case where the subset indicator 1503 indicates thesubset 1 and the shift indicator 1506 indicates ‘shift 0’, the remaining8 bits of the bitmap are used to indicate RB0, RB1, RB2, RB9, RB10,RB11, RB18 and RB19 (see 1504). On the other hand, in the case where thesubset indicator 1503 indicates the subset 1 and the shift indicator1506 indicates ‘shift 1’, the remaining 8 bits of the bitmap are used toindicate RB10, RB11, RB18, RB19, RB20, RB27, RB28 and RB29 (see 1505).

Although the subset indicator 1503 has been described in the aboveexample to indicate the subset 1 1504 or 1505, it may indicate thesubset 2 or subset 3. Accordingly, it can be seen that eight RBs can bemapped in units of one RB with respect to each combination of the subsetindicator 1503 and shift indicator 1506. Also, referring to FIG. 15, inthe present embodiment, the numbers of RBs assigned to the subset 1,subset 2 and subset 3 are 12, 11 and 9 which are different,respectively. Accordingly, it can be seen that four RBs cannot be usedin the case of the subset 1, three RBs cannot be used in the case of thesubset 2 and one RB cannot be used in the case of the subset 3 (seeshaded areas). FIG. 15 is nothing but an illustration, and the presentembodiment is thus not limited thereto.

Consideration can be given to use of a combination of the bitmap schemeusing the RBG scheme and subset scheme and the compact scheme.

FIG. 16 illustrates an example of a method for mapping based on acombination of the bitmap scheme and compact scheme.

In the case where DVRBs are mapped and transmitted as shown in FIG. 16,some resource elements of an RBG0, RBG1, RBG2 and RBG4 are filled by theDVRBs. The RBG0, among them, is included in a subset 1, the RBG1 andRBG4 are included in a subset 2, and the RBG2 is included in a subset 3.At this time, it is impossible to allocate the RBG0, RBG1, RBG2 and RBG4to UEs in the RBG scheme. Also, RBs (PRB0, PRB4, PRB8 and PRB12) in theRBGs left after being assigned as DVRBs must be allocated to UEs in thesubset scheme. However, because a UE allocated in the subset scheme canbe allocated only an RB in one subset, the remaining RBs belonging toother subsets cannot help being allocated to different UEs. As a result,LVRB scheduling is restricted by DVRB scheduling.

Therefore, there is a need for a DVRB arrangement method capable ofreducing the restriction in the LVRB scheduling.

Third to fifth embodiments of the present invention are directed tomethods for setting a relative distance between divided parts of a DVRBmapped to PRBs to reduce an effect on LVRBs.

Embodiment 3

The embodiment 3 is directed to a method for, when mapping divided partsof DVRBs, mapping the divided parts to RBs belonging to one specificsubset and then mapping the divided parts to RBs belonging to othersubsets after mapping the divided parts to all the RBs of the specificsubset.

According to this embodiment, when consecutive DVRB indexes are mappedto distributed PRBs, they can be distributively mapped within one subsetand then mapped to other subsets when they cannot be mapped within theone subset any longer. Also, interleaving of consecutive DVRBs isperformed within a subset.

FIGS. 17 and 18 illustrate a DVRB mapping method according to oneembodiment of the present invention.

DVRB0 to DVRB11 are distributively mapped within a subset 1 (1703),DVRB12 to DVRB22 are then distributively mapped within a subset 2(1704), and DVRB23 to DVRB31 are then distributively mapped within asubset 3 (1705). This mapping can be carried out by a method of using ablock interleaver for each subset or any other method.

This arrangement can be achieved by controlling a block interleaveroperation scheme.

Embodiment 4

The embodiment 4 is directed to a method for limiting mapping of dividedDVRB parts to PRBs included in the same subset.

In the embodiment 4, gap information can be used to map divided parts ofthe same DVRB within the same subset. At this time, a parameter for allPRBs, such as the aforementioned ‘Gap’, may be used. Alternatively,another parameter for one subset, ‘Gap_(subset)’ may be used. This willhereinafter be described in detail.

It is possible to together use a method for distributively fillingconsecutive DVRBs within one subset and a method for mapping dividedparts of each DVRB within the same subset. In this case, preferably,Gap_(subset), which means a difference between PRB numbers within thesame subset, can be used as information indicative of a relativeposition difference between divided DVRB parts. The meaning ofGap_(subset) can be understood from FIG. 17. PRBs included in the subset1 are a PRB0, PRB1, PRB2, PRB9, PRB10, PRB11, PRB18, PRB19, PRB20,PRB27, PRB28 and PRB29. Here, the PRB18 is spaced apart from the PRB0within the subset 1 by 6 (Gap_(subset)=6) indexes. On the other hand,with respect to all PRBs, the PRB18 can be indicated to be spaced apartfrom the PRB0 by 18 (Gap=18) indexes.

Embodiment 5

The embodiment 5 is directed to a method for setting a relative distancebetween divided DVRB parts to a multiple of the square of the size of anRBG.

The limited setting of Gap to a multiple of the size of an RBG as in thepresent embodiment provides characteristics as follows. That is, whenthe relative distance between the divided DVRB parts is indicated as arelative position difference within one subset, it is set to a multipleof the size (P) of an RBG. Alternatively, when the relative distancebetween the divided DVRB parts is indicated as a position differencewith respect to all PRBs, it is limited to a multiple of the square (P²)of the RBG size.

For example, referring to FIG. 15, it can be seen that P=3 and P²=9.Here, it can be seen that the relative distance between a first dividedpart 1701 and second divided part 1702 of a DVRB is a multiple of P (=3)because Gap_(subset)=6, and a multiple of P² (=9) because Gap=18.

In the case where a scheme based on this embodiment is used, because theprobability that RBGs only some resource elements of each of which areused will belong to the same subset is high, it is expected thatresource elements or RBs left not used are present in the same subset.Therefore, it is possible to efficiently use allocation of the subsetscheme.

Referring to FIG. 17, because the size of an RBG10 is 2, it is differentfrom the sizes (=3) of other RBGs. In this case, for the convenience ofDVRB index arrangement, the RBG10 may not be used for DVRBs. Also,referring to FIGS. 17 and 18, a total of four RBGs including an RBG9belong to the subset 1, a total of three RBGs, if excluding the RBG10,belong to the subset 2, and a total of three RBGs belong to the subset3. Here, for the convenience of DVRB index arrangement, the RBG9, amongthe four RBGs belonging to the subset 1, may not be used for DVRBs.Thus, a total of three RBGs per subset may be used for DVRBs.

In this case, DVRB indexes can be sequentially mapped to one subset (forexample, subset 1) used for DVRBs, among the subsets, as shown in FIG.18. If the DVRB indexes cannot be mapped to the one subset any longer,they can be mapped to a next subset (for example, subset 2).

On the other hand, it can be seen that DVRB indexes are consecutivelyarranged in FIG. 11, but non-consecutively arranged in FIGS. 12, 13, 14,16, 17 and 18. In this manner, DVRB indexes can be changed inarrangement before being mapped to PRB indexes, and this change can beperformed by a block interleaver. Hereinafter, the structure of a blockinterleaver according to the present invention will be described.

Embodiment 6

Hereinafter, a description will be given of a method for configuring aninterleaver having a desired degree equal to a diversity order,according to one embodiment of the present invention.

In detail, in a method for mapping consecutive DVRB indexes tonon-contiguous, distributed PRBs, a method is proposed which uses ablock interleaver and configures the interleaver such that it has adegree equal to a target diversity order N_(DivOrder). The degree of theinterleaver can be defined as follows.

That is, in a block interleaver having m rows and n columns, when datais written, the data is written while the index thereof is sequentiallyincremented. At this time, the writing is performed in such a mannerthat, after one column is completely filled, a column index isincremented by one and a next column is filled. In each column, thewriting is performed while a row index is incremented. For reading fromthe interleaver, the reading is performed in such a manner that, afterone row is completely read, a row index is incremented by one and a nextrow is read. In this case, the interleaver can be referred to as anm-degree interleaver.

Conversely, in a block interleaver having m rows and n columns, datawriting may be performed in such a manner that, after one row is filled,the process proceeds to a next row, and data reading may be performed insuch a manner that, after one column is read, the process proceeds to anext column. In this case, the interleaver can be referred to as ann-degree interleaver.

In detail, N_(DivOrder) is limited to a multiple of N_(D). That is,N_(DivOrder)=K≮N_(D). Here, K is a positive integer. Also, a blockinterleaver of a degree N_(DivOrder) is used.

FIG. 19 is an illustration when the number of RBs used in interleavingis N_(DVRB)=24 and N_(D)=2 and N_(Divorder)=2×3=6.

Referring to FIG. 19, for writing into an interleaver, data is writtenwhile the index thereof is sequentially incremented. At this time, thewriting is performed in such a manner that, after one column iscompletely filled, a column index is incremented by one and a nextcolumn is filled. In one column, the writing is performed while a rowindex is incremented. For reading from the interleaver, the reading isperformed in such a manner that, after one row is completely read, a rowindex is incremented by one and a next row is read. In one row, thereading is performed while a column index is incremented. In the casewhere the reading/writing is performed in this manner, the degree of theinterleaver is the number of rows, which is set to a target diversityorder, 6.

In the case where the interleaver is configured in this manner, a DVRBindex order of a data sequence outputted from the interleaver can beused as an index order of first divided parts of DVRBs, and a DVRB indexorder of a data sequence obtained by cyclically shifting the outputteddata sequence by N_(DVRB)/N_(D) can be used as an index order of theremaining divided parts. As a result, N_(D) divided parts generated fromDVRBs are mapped to only N_(D) PRBs in pairs, and the difference betweenpaired DVRB indexes is K.

For example, in FIG. 19, N_(DVRB)/N_(D)=N_(DVRB) (=24)/N_(D)(=2)=24/2=12, and K=3. It can also be seen from FIG. 19 that a DVRBindex order 1901 of a data sequence outputted from the interleaver isgiven as“0→6→12→18→1→7→13→19→2→8→14→20→3→9→15→21→4→10→16→22→5→11→17→23”, and aDVRB index order 1902 of a data sequence obtained by cyclically shiftingthe outputted data sequence by N_(DVRB)/N_(D)=12 is given as“3→9→15→21→4→10→16→22→5→11→17→23→0→6→12→18→1→7→13→19→2→8→14→20”. Also,DVRBs are paired. Referring to 1903 of FIG. 19, for example, it can beseen that a DVRB0 and a DVRB3 are paired. It can also be seen thatrespective combinations of divided parts generated from the DVRB0 andDVRB3 are mapped to a PRB0 and a PRB12, respectively. This is similarlyapplied to other DVRBs having other indexes.

According to this embodiment, it is possible to effectively manage therelationship between DVRBs and PRBs to which the DVRBs are mapped.

Embodiment 7

Hereinafter, a method for filling nulls in a rectangular interleaver inaccordance with one embodiment of the present invention will bedescribed.

In the following description, the number of nulls filled in theinterleaver may be represented by “N_(null)”.

In accordance with the embodiment 6, it is possible to completely filldata in the interleaver because N_(DVRB) is a multiple of N_(DivOrder).However, when N_(DVRB) is not a multiple of N_(DivOrder), it isnecessary to take a null filling method into consideration because it isimpossible to completely fill data in the interleaver.

For a cyclic shift by N_(DVRB)/N_(D), N_(DVRB) should be a multiple ofN_(D). In order to completely fill data in a rectangular interleaver,N_(DVRB) should be a multiple of N_(DivOrder). However, when K>1,N_(DVRB) may not be a multiple of N_(DivOrder), even though it is amultiple of N_(D). In this case, generally, data is sequentially filledin the block interleaver, and nulls are then filled in remaining spacesof the block interleaver. Thereafter, reading is performed. If the datais filled column by column, then the data is read row by row, or if thedata is filled row by row, then the data is read column by column. Inthis case, no reading is performed for nulls.

FIGS. 20A and 20B illustrate a general block interleaver operation whenthe number of RBs used in an interleaving operation is 22, namely,N_(DVRB)=22, N_(D)=2, and N_(DivOrder)=2×3=6, that is, when N_(DVRB) isnot a multiple of N_(DivOrder).

Referring to FIG. 20A, the index difference between paired DVRBs has arandom value. For example, DVRB pairs (0, 20), (6, 3), and (12, 9)(indicated by “2001”, “2002”, and “2003”) have index differences of 20(20−0=20), 3 (6−3=3), and 3 (12−9=3), respectively. Accordingly, it canbe seen that the index difference between paired DVRBs is not fixed to acertain value. For this reason, the scheduling of DVRBs getscomplicated, as compared to the case in which the index differencebetween paired DVRBs has a fixed value.

Meanwhile, when it is assumed that N_(Remain) represents a remainderwhen N_(DVRB) is divided by N_(DivOrder), nulls are filled in elementsof a last column, except for elements corresponding to N_(Remain)values, as shown in FIG. 20A or 20B. For example, referring to FIG. 20A,nulls may be filled in two elements of the last column, except for fourelements corresponding to four values, because the remainder whenN_(DVRB) (=22) is divided by N_(DivOrder) (=6) is 4 (N_(Remain)=4).Although nulls are rearwardly filled in the above example, they may bepositioned before a first index value. For example, the N_(Remain)values are filled in elements, starting from a first element. Also,nulls may be arranged at predetermined positions, respectively.

FIGS. 21A and 21B illustrates a null arranging method according to oneembodiment of the present invention. Referring to FIGS. 21A and 21B, itcan be seen that nulls are uniformly distributed, as compared to thecase of FIGS. 20A and 20B.

In this embodiment, when nulls are to be filled in a rectangular blockinterleaver, N_(DivOrder) corresponding to the degree of the interleaveris divided into N_(D) groups each having a size of K, and nulls areuniformly distributed in all the groups. For example, as shown in FIG.21A, the interleaver may be divided into N_(D) (=2) groups G2101 andG2102. In this case, K=3. One null is written in the first group G2101.Similarly, one null is written in the second group G2102. Thus, nullsare distributively written.

For example, where writing is performed in such a manner that values aresequentially filled, N_(Remain) values remain finally. When indexescorresponding to the remaining values are arranged in N_(D) groups suchthat they are uniformly distributed, it is possible to uniformly arrangenulls. For example, in the case of FIG. 21A, N_(Remain)(=4) data spacesremain. When indexes 18, 19, 20, and 21 corresponding to the data spacesare arranged in N_(D) (=2) groups such that they are uniformlydistributed, it is possible to arrange one null in each group.

As a result, the difference between paired DVRB indexes can bemaintained to be K or less (for example, K=3). Accordingly, there is anadvantage in that a more efficient DVRB allocation can be achieved.

Embodiment 8

Hereinafter, a method for setting a relative distance between dividedparts of each DVRB mapped to PRBs to 0 in accordance with one embodimentof the present invention will be described.

FIG. 22 illustrates a method for mapping interleaved DVRB indexes whileGap=0 in accordance with one embodiment of the present invention.

Meanwhile, where M DVRBs are allocated to one UE in a scheme for mappingconsecutive DVRB indexes to non-contiguous, distributed PRBs, areference value M_(th) for M may be set. Based on the reference valueM_(th), the divided parts of each DVRB may be distributively assigned todifferent PRBs, respectively, to raise the diversity order.Alternatively, the divided parts of each DVRB may be assigned to thesame PRB without being distributed to different PRBs. In this case, itis possible to reduce the number of PRBs, to which DVRBs aredistributively mapped, and thus to limit the diversity order.

That is, this method is a scheme in which the divided parts of each DVRBare distributed to raise the diversity order, when M is less than aspecific reference value (=M_(th)), whereas, when M is not less than thespecific reference value (=M_(th)), the divided parts of each DVRB areassigned to the same PRB without being distributed, to reduce the numberof PRBs, to which DVRBs are distributively mapped, and thus to limit thediversity order.

That is, in this scheme, DVRB indexes of a data sequence outputted fromthe interleaver are applied, in common, to all divided parts of eachDVRB such that they are mapped to PRBs, as shown in FIG. 22. Forexample, referring to FIG. 9, DVRB indexes of a data sequence outputtedfrom the interleaver have an order of“0→6→12→18→1→7→13→19→2→8→14→20→3→9→15→21→4→10→16→22→5→11→17→23”. In thiscase, each data sequence DVRB index is applied, in common, to first andsecond divided parts 2201 and 2202 of each DVRB.

Embodiment 9

Hereinafter, a method, in which both the above-described embodiments 6and 8 are used, will be described in accordance with one embodiment ofthe present invention.

FIG. 23 illustrates the case in which a UE1, which is subjected to ascheduling in a scheme of mapping respective divided parts of each DVRBto different PRBs, as shown in FIG. 19, and a UE2, which is subjected toa scheduling in a scheme of mapping the divided parts of each DVRB tothe same PRB, as shown in FIG. 22, are simultaneously multiplexed. Thatis, FIG. 23 illustrates the case in which the UE1 and UE2 aresimultaneously scheduled in accordance with the methods of theembodiments 6 and 8, respectively.

For example, referring to FIG. 23, the UE1 is allocated a DVRB0, DVRB1,DVRB2, DVRB3, and DVRB4 (2301), whereas the UE2 is allocated a DVRB6,DVRB7, DVRB8, DVRB9, DVRB10, and DVRB11 (2302). However, the UE1 isscheduled in such a manner that the divided parts of each DVRB aremapped to different PRBs, respectively, whereas the UE2 is scheduled insuch a manner that the divided parts of each DVRB are mapped to the samePRB. Accordingly, the PRBs used for the UE1 and UE2 include a PRB0,PRB1, PRB4, PRB5, PRB8, PRB9, PRB12, PRB13, PRB16, PRB17, PRB20, andPRB21, as shown by “2303” in FIG. 23. In this case, however, the PRB8and PRB20 are partially used.

Where the divided parts of each DVRB are mapped to distributed PRBs,respectively, the difference between the paired DVRB indexes is limitedto a value of K or less. Accordingly, this scheme has no influence onDVRBs spaced apart from each other by a gap of more than K. Accordingly,it is possible to easily distinguish indexes usable in the “case inwhich the divided parts of each DVRB are mapped to the same PRB” fromunusable indexes.

Embodiment 10

Hereinafter, a method for limiting an N_(DVRB), to prevent generation ofa null, will be described in accordance with one embodiment of thepresent invention.

Again referring to FIG. 20, it can be seen that the difference betweenthe DVRB indexes paired for PRBs may not be fixed to a specific value.In order to reduce the DVRB index difference to a specific value orless, the method of FIG. 21 may be used as described above.

When the method of FIG. 21 is used to distribute nulls, the complexityof the interleaver increases due to the processing of nulls. In order toprevent such a phenomenon, a method for limiting N_(DVRB) such that nonull is generated may be taken into consideration.

In the illustrated interleaver, the number of RBs used for DVRBs,namely, N_(DVRB), is limited to a multiple of the diversity order,namely, N_(DivOrder), so that no null is filled in a rectangular matrixof the interleaver.

In a block interleaver of degree D, no null is filled in the rectangularmatrix of the interleaver when the number of RBs used for DVRBs, namely,N_(DVRB), is limited to a multiple of D.

Hereinafter, several embodiments using the interleaver according to thepresent invention when K=2, and N_(D)=2 will be described. The relationbetween DVRB and PRB indexes may be expressed by a mathematicexpression.

FIG. 24 is a view for explaining the relation between DVRB and PRBindexes.

Referring to the following description and FIG. 24, parameters used inmathematic expressions can be understood.

p: PRB index (0≦p≦N_(DVRB)−1)

d: DVRB index (0≦d≦N_(DVRB)−1)

p_(1,d): Index of a first slot of a PRB to which a given DVRB index d ismapped

p_(2,d): Index of a second slot of a PRB to which a given DVRB index dis mapped

d_(p) ₁ : DVRB index included in a first slot of a given PRB index p

d_(p) ₂ : DVRB index included in a second slot of a given PRB index p

Constants used in Expressions 1 to 11 expressing the relation betweenDVRB and PRB indexes are defined as follows.

C: Number of columns of the block interleaver

R: Number of rows of the block interleaver

N_(DVRB): Number of RBs used for DVRBs

R=┌N _(DVRB) /C┐

N_(PRB): Number of PRBs in the system bandwidth.

FIG. 25A is a view for explaining the above-described constants.

When K=2, N_(D)=2, and N_(DVRB) is a multiple of C, the relation betweenPRB and DVRB indexes may be derived using Expressions 1 to 3. First, ifa PRB index p is given, a DVRB index can be derived using Expression 1or 2. In the following description, “mod(x,y)” means “x mod y”, and“mod” means a modulo operation. Also, “└•┘” means a descendingoperation, and represents a largest one of integers equal to or smallerthan a numeral indicated in “└ ┘”. On the other hand, “┌•┐” means anascending operation, and represents a smallest one of integers equal toor larger than a numeral indicated in “┌ ┐”. Also, “round(•)” representsan integer nearest to a numeral indicated in “( )”. “min(x,y)”represents the value which is not larger among x and y, whereas“max(x,y)” represents the value which is not smaller among x and y.

d _(p1)=mod(p,R)·C+└p/R┘

d _(p2)=mod(p′,R)·C+└p′/R┘  [Expression 1]

where p′=mod(p+N_(DVRB)/2,N_(DVRB))

$\begin{matrix}{\mspace{79mu} {{d_{p_{1}} = {{{{mod}\left( {p^{\;},R} \right)} \cdot C} + \left\lfloor {p^{\;}/R} \right\rfloor}}\mspace{79mu} {d_{p_{2}} = \left\{ \begin{matrix}{{d_{p_{1}} - 2},\; {{{when}{\; \;}{{mod}\left( {d_{p_{1}},C} \right)}}2}} \\{{d_{p_{1}} + 2},{{{when}{\; \;}{{mod}\left( {d_{p_{1}},C} \right)}} < 2}}\end{matrix}\; \right.}}} & \left\lbrack {{Expression}\mspace{11mu} 2} \right\rbrack\end{matrix}$

On the other hand, when N_(DVRB) is a multiple of C, and a DVRB index dis given, a PRB index can be derived using Expression 3.

p _(1,d)=mod(d,C)·R+└d/C┘

p _(2,d)=mod(p _(1,d) +N _(DVRB)/2,N _(DVRB))  [Expression 3]

FIG. 25B illustrates a general method for filling nulls in aninterleaver. This method is applied to the case in which K=2, N_(D)=2,and N_(DVRB) is a multiple of N_(d). The method of FIG. 25B is similarto the method of FIGS. 20A and 20B. In accordance with the method ofFIG. 25B, if a PRB index p is given, a DVRB index can be derived usingExpression 4.

$\begin{matrix}{\mspace{20mu} {{d_{p_{1}} = {{{{mod}\left( {p^{\prime},R} \right)} \cdot C} + \left\lfloor {p^{\prime}/R} \right\rfloor}}\mspace{20mu} {where}{p^{\prime} = \left\{ {{\begin{matrix}{{p + 1},} & {{{when}\mspace{14mu} {{mod}\left( {N_{RB}^{\prime},C} \right)}} \neq {0\mspace{14mu} {and}\mspace{14mu} p} \geq {{3R} - 1}} \\{p,} & {{{when}\mspace{14mu} {{mod}\left( {N_{RB}^{\prime},C} \right)}} = {{0\mspace{14mu} {or}\mspace{14mu} p} < {{3R} - 1}}}\end{matrix}\mspace{20mu} d_{p_{2}}} = {{{{{mod}\left( {p^{''},R} \right)} \cdot C} + {\left\lfloor {p^{''}/R} \right\rfloor \mspace{20mu} {where}p^{''}}} = \left\{ {{\begin{matrix}{{p^{\prime\prime\prime} + 1},} & {{{when}\mspace{14mu} {{mod}\left( {N_{RB}^{\prime},C} \right)}} \neq {0\mspace{14mu} {and}\mspace{14mu} p^{\prime\prime\prime}} \geq {{3R} - 1}} \\{p^{\prime\prime\prime},} & {{{when}\mspace{14mu} {{mod}\left( {N_{RB}^{\prime},C} \right)}} = {{0\mspace{14mu} {or}\mspace{14mu} p^{\prime\prime\prime}} < {{3R} - 1}}}\end{matrix}\mspace{20mu} {where}\mspace{14mu} p^{\prime\prime\prime}} = {{mod}\left( {{p + {N_{DVRB}/2}},N_{DVRB}} \right)}} \right.}} \right.}}} & \left\lbrack {{Expression}\mspace{14mu} 4} \right\rbrack\end{matrix}$

On the other hand, if a DVRB index d is given, a PRB index can bederived using Expression 5.

$\begin{matrix}{p_{1,d} = \left\{ {{\begin{matrix}{{p_{1,d}^{\prime} - 1},} & {{{{when}\mspace{14mu} {{mod}\left( {N_{RB}^{\prime},C} \right)}} \neq {0\mspace{14mu} {and}\mspace{14mu} {{mod}\left( {d,C} \right)}}} = 3} \\{p_{d}^{\prime},} & {{{when}\mspace{14mu} {{mod}\left( {N_{RB}^{\prime},C} \right)}} = {{0\mspace{14mu} {or}\mspace{14mu} {{mod}\left( {d,C} \right)}} \neq 3}}\end{matrix}\mspace{20mu} {where}\mspace{14mu} p_{1,d}^{\prime}} = {{{{{mod}\left( {d,C} \right)} \cdot R} + {\left\lfloor {d/C} \right\rfloor \mspace{20mu} p_{2,d}}} = {{mod}\left( {{p_{1,d} + {N_{DVRB}/2}},N_{DVRB}} \right)}}} \right.} & \left\lbrack {{Expression}\mspace{14mu} 5} \right\rbrack\end{matrix}$

Embodiment 11

FIG. 25C illustrates a method for filling nulls in an interleaver inaccordance with one embodiment of the present invention. This method isapplied to the case in which K=2, N_(D)=2, and N_(DVRB) is a multiple ofN_(d).

FIG. 25C illustrates a method corresponding to the method of theembodiment 7 and FIGS. 21A and 21B. The method of FIG. 25C may beexplained using Expressions 6 to 8. In accordance with the method ofFIG. 25C, if a PRB index p is given, a DVRB index can be derived usingExpression 6 or 7.

$\begin{matrix}{\mspace{25mu} {{d_{p_{1}} = {{{{mod}\left( {p^{\prime},R} \right)} \cdot C} + \left\lfloor {p^{\prime}/R} \right\rfloor}}\mspace{20mu} {where}{p^{\prime} = \left\{ {{\begin{matrix}{{p + 1},} & {\mspace{14mu} \begin{matrix}{{{when}\mspace{14mu} {{mod}\left( {N_{DVRB},C} \right)}} \neq {0\mspace{14mu} {and}}} \\{p \geq {{2R} - {1\mspace{14mu} {and}\mspace{14mu} p}} \neq {{3R} - 2}}\end{matrix}} \\{{{2R} - 1},} & \begin{matrix}{{{when}\mspace{14mu} {{mod}\left( {N_{DVRB},C} \right)}} \neq {0\mspace{14mu} {and}}} \\{p = {{3R} - 2}}\end{matrix} \\{p,} & {{{when}\mspace{14mu} {{mod}\left( {N_{DVRB},C} \right)}} = {{0\mspace{14mu} {or}\mspace{14mu} p} < {{2R} - 1}}}\end{matrix}\mspace{20mu} d_{p_{2}}} = {{{{{mod}\left( {p^{''},R} \right)} \cdot C} + {\left\lfloor {p^{''}/R} \right\rfloor \mspace{20mu} {where}p^{''}}} = \left\{ {{\begin{matrix}{{p^{\prime\prime\prime} + 1},} & \begin{matrix}{{{when}\mspace{14mu} {{mod}\left( {N_{DVRB},C} \right)}} \neq {0\mspace{14mu} {and}}} \\{p^{\prime\prime\prime} \geq {{2R} - {1\mspace{14mu} {and}\mspace{14mu} p^{\prime\prime\prime}}} \neq {{3R} - 2}}\end{matrix} \\{{{2R} - 1},} & {{{{when}\mspace{14mu} {{mod}\left( {N_{DVRB},C} \right)}} \neq {0\mspace{14mu} {and}\mspace{14mu} p^{\prime\prime\prime}}} = {{3R} - 2}} \\{p^{\prime\prime\prime},} & {{{{when}\mspace{14mu} {{mod}\left( {N_{DVRB},C} \right)}} = {0\mspace{14mu} {or}\mspace{14mu} p^{\prime\prime\prime}}},{{2R} - 1}}\end{matrix}\mspace{20mu} {where}\mspace{14mu} p^{\prime\prime\prime}} = {{mod}\left( {{p + {N_{DVRB}/2}},N_{DVRB}} \right)}} \right.}} \right.}}} & \left\lbrack {{Expression}\mspace{14mu} 6} \right\rbrack\end{matrix}$

$\begin{matrix}{\mspace{20mu} {{d_{p_{1}} = {{{{mod}\left( {p^{\prime},R} \right)} \cdot C} + \left\lfloor {p^{\prime}/R} \right\rfloor}}\mspace{20mu} {where}{p^{\prime} = \left\{ \begin{matrix}{{p + 1},} & \begin{matrix}{{{when}\mspace{14mu} {{mod}\left( {N_{DVRB},C} \right)}} \neq {0\mspace{14mu} {and}}} \\{p \geq {{2R} - {1\mspace{14mu} {and}\mspace{14mu} p}} \neq {{3R} - 2}}\end{matrix} \\{{{2R} - 1},} & {{{{when}\mspace{14mu} {{mod}\left( {N_{DVRB},C} \right)}} \neq {0\mspace{14mu} {and}\mspace{14mu} p}} = {{3R} - 2}} \\{p,} & {{{when}\mspace{14mu} {{mod}\left( {N_{DVRB},C} \right)}} = {{0\mspace{14mu} {or}\mspace{14mu} p} < {{2R} - 1}}}\end{matrix} \right.}}} & \left\lbrack {{Expression}\mspace{14mu} 7} \right\rbrack \\{d_{p_{2}} = \left\{ \begin{matrix}{{d_{p_{1}} - 2},} & {{{when}\mspace{14mu} {{mod}\left( {d_{p_{1}},C} \right)}} \geq 2} \\{{d_{p_{1}} + 2},} & \begin{matrix}{{{when}\mspace{14mu} {{mod}\left( {d_{p_{1}},C} \right)}} < 2} \\{{{and}\mspace{14mu} d_{p_{1}}} \neq {N_{DVRB} - {2\mspace{14mu} {and}\mspace{14mu} d_{p_{1}}}} \neq {N_{DVRB} - 1}}\end{matrix} \\{{N_{DVRB} - 1},} & \begin{matrix}{{{when}\mspace{14mu} {{mod}\left( {d_{p_{1}},C} \right)}} < 2} \\{{{and}\mspace{14mu} d_{p_{1}}} = {N_{DVRB} - 2}}\end{matrix} \\{{N_{DVRB} - 2},} & \begin{matrix}{{{when}\mspace{14mu} {{mod}\left( {d_{p_{1}},C} \right)}} < 2} \\{{{and}\mspace{14mu} d_{p_{1}}} = {N_{DVRB} - 1}}\end{matrix}\end{matrix} \right.} & \;\end{matrix}$

On the other hand, in the method of FIG. 25C, if a DVRB index d isgiven, a PRB index can be derived using Expression 8.

$\begin{matrix}{p_{1,d} = \left\{ {{\begin{matrix}{{p_{1,d}^{\prime} - 1},} & \begin{matrix}{{{when}\mspace{14mu} {{mod}\left( {N_{DVRB},C} \right)}} \neq 0} \\{{{and}\mspace{14mu} {{mod}\left( {d,C} \right)}} \geq 2}\end{matrix} \\{{{3R} - 2},} & \begin{matrix}{{{when}\mspace{14mu} {{mod}\left( {N_{DVRB},C} \right)}} \neq 0} \\{{{and}\mspace{14mu} d} = {N_{DVRB} - 1}}\end{matrix} \\{p_{1,d}^{\prime},} & \begin{matrix}{{{when}\mspace{14mu} {{mod}\left( {N_{DVRB},C} \right)}} = {0\mspace{14mu} {or}}} \\\left( {{{mod}\left( {d,C} \right)} < {2\mspace{14mu} {and}\mspace{14mu} d} \neq {N_{DVRB} - 1}} \right)\end{matrix}\end{matrix}\mspace{20mu} {where}\mspace{14mu} p_{1,d}^{\prime}} = {{{{{mod}\left( {d,C} \right)} \cdot R} + {\left\lfloor {d/C} \right\rfloor \mspace{20mu} p_{2,d}}} = {{mod}\left( {{p_{1,d} + {N_{DVRB}/2}},N_{DVRB}} \right)}}} \right.} & \left\lbrack {{Expression}\mspace{14mu} 8} \right\rbrack\end{matrix}$

Embodiment 12

FIG. 25D illustrates a method implemented using the method of theembodiment 7 and FIGS. 21A and 21B when K=2, N_(D)=2, and the size ofthe interleaver (=C×R) is set such that C·R=N_(DVRB)+N_(null). Here,“N_(null)” represents the number of nulls to be included in theinterleaver. This value N_(null) may be a predetermined value. Inaccordance with this method, if a DVRB index p is given, a DVRB indexcan be derived using Expression 9 or 10.

$\begin{matrix}{\mspace{20mu} {{d_{p_{1}} = {{{{mod}\left( {p^{\prime},R} \right)} \cdot C} + \left\lfloor {p^{\prime}/R} \right\rfloor}}\mspace{20mu} {where}{p^{\prime} = \left\{ {{\begin{matrix}{p,} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} = {{0\mspace{14mu} {or}\mspace{14mu} p} < {R - {N_{null}/2}}}} \\{{{or}\mspace{14mu} R} \leq p < {{2R} - {N_{null}/2}}}\end{matrix} \\{{p + {N_{null}/2}},} & \begin{matrix}{{{when}\mspace{14mu} N_{nulll}} \neq {0\mspace{14mu} {and}}} \\\begin{pmatrix}{{{2R} - {N_{null}/2}} \leq p < {{3R} - {N_{null}\mspace{14mu} {or}}}} \\{p \geq {{3R} - {N_{null}/2}}}\end{pmatrix}\end{matrix}\end{matrix}\mspace{20mu} d_{p_{1}}} = {{{{{mod}\left( {p^{\prime},{2R}} \right)} \cdot {C/2}} + {\left\lfloor {{p^{\prime}/2}R} \right\rfloor \mspace{20mu} {where}p^{\prime}}} = \left\{ \begin{matrix}{{p + R - {N_{null}/2}},} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} \neq {0\mspace{14mu} {and}}} \\{{R - {N_{null}/2}} \leq p < R}\end{matrix} \\{{p + R},} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} \neq {0\mspace{14mu} {and}}} \\{{{3R} - N_{null}} \leq p < {{3R} - {N_{null}/2}}}\end{matrix}\end{matrix} \right.}} \right.}}} & \left\lbrack {{Expression}\mspace{14mu} 9} \right\rbrack\end{matrix}$

$\begin{matrix}{\mspace{20mu} {{d_{p_{2}} = {{{{mod}\left( {p^{''},R} \right)} \cdot C} + \left\lfloor {p^{''}/R} \right\rfloor}}\mspace{20mu} {where}{p^{''} = \left\{ {{\begin{matrix}{p^{\prime\prime\prime},} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} = {{0\mspace{14mu} {or}\mspace{14mu} p^{\prime\prime\prime}} < {R - {N_{null}/2}}}} \\{{{or}\mspace{14mu} R} \leq p^{\prime\prime\prime} < {{2R} - {N_{null}/2}}}\end{matrix} \\{{p^{\prime\prime\prime} + {N_{null}/2}},} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} \neq {0\mspace{14mu} {and}}} \\\begin{pmatrix}{{{2R} - N_{null}} \leq p^{\prime\prime\prime} < {{3R} - {N_{null}\mspace{14mu} {or}}}} \\{p^{\prime\prime\prime} \geq {{3R} - {N_{null}/2}}}\end{pmatrix}\end{matrix}\end{matrix}\mspace{20mu} d_{p_{2\;}}} = {{{{{mod}\left( {p^{''},{2R}} \right)} \cdot {C/2}} + {\left\lfloor {{p^{''}/2}R} \right\rfloor \mspace{20mu} {where}p^{''}}} = \left\{ {{\begin{matrix}{{p^{\prime\prime\prime} + R - {N_{null}/2}},} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} \neq {0\mspace{14mu} {and}}} \\{{R - {N_{null}/2}} \leq p^{\prime\prime\prime} < R}\end{matrix} \\{{p^{\prime\prime\prime} + R},} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} \neq {0\mspace{14mu} {and}}} \\{{{3R} - N_{null}} \leq p^{\prime\prime\prime} < {{3R} - {N_{null}/2}}}\end{matrix}\end{matrix}\mspace{20mu} {where}\mspace{14mu} p^{\prime\prime\prime}} = {{mod}\left( {{p + {N_{RB}^{\prime}/2}},N_{RB}^{\prime}} \right)}} \right.}} \right.}}} & \left\lbrack {{Expression}\mspace{14mu} 10} \right\rbrack\end{matrix}$

On the other hand, if a DVRB index d is given, a PRB index can bederived using Expression 11.

$\begin{matrix}{p_{1,d} = \left\{ {{\begin{matrix}{p_{1,d}^{\prime},} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} = {0\mspace{14mu} {or}}} \\\begin{pmatrix}{d < {N_{DVRB} - {N_{null}\mspace{14mu} {and}}}} \\{{{mod}\left( {d,C} \right)} < 2}\end{pmatrix}\end{matrix} \\{{p_{1,d}^{\prime} - {N_{null}/2}},} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} \neq {0\mspace{14mu} {and}}} \\\begin{pmatrix}{d < {N_{DVRB} - {N_{null}\mspace{14mu} {and}}}} \\{{{mod}\left( {d,C} \right)} \geq 2}\end{pmatrix}\end{matrix}\end{matrix}\mspace{20mu} {where}},{p_{1,d}^{\prime} = {{{{{mod}\left( {d,C} \right)} \cdot R} + {\left\lfloor {d/C} \right\rfloor p_{1,d}}} = \left\{ {{\begin{matrix}{{p_{1,d}^{\prime} - R + {N_{null}/2}},} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} \neq {0\mspace{14mu} {and}}} \\\begin{pmatrix}{d \geq {N_{DVRB} - {N_{null}\mspace{14mu} {and}}}} \\{{{mod}\left( {d,{C/2}} \right)} = 0}\end{pmatrix}\end{matrix} \\{{p_{1,d}^{\prime} - R},} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} \neq {0\mspace{14mu} {and}}} \\\begin{pmatrix}{d \geq {N_{DVRB} - {N_{null}\mspace{14mu} {and}}}} \\{{{mod}\left( {d,{C/2}} \right)} = 1}\end{pmatrix}\end{matrix}\end{matrix}\mspace{20mu} {where}\mspace{14mu} p_{1,d}^{\prime}} = {{{{{{mod}\left( {d,{C/2}} \right)} \cdot 2}R} + {\left\lfloor {2{d/C}} \right\rfloor \mspace{20mu} p_{2,d}}} = {{mod}\left( {{p_{1,d} + {N_{DVRB}/2}},N_{DVRB}} \right)}}} \right.}}} \right.} & \left\lbrack {{Expression}\mspace{14mu} 11} \right\rbrack\end{matrix}$

Again referring to the description given with reference to FIG. 15, thecase, in which a combination of the bitmap scheme using the RBG schemeand subset scheme and the compact scheme are used, may be taken intoconsideration. Problems possibly occurring in this case will bedescribed with reference to FIGS. 26 and 27.

FIGS. 26 and 27 illustrate examples of a method using a combination ofthe bitmap scheme using the RBG scheme and subset scheme and the compactscheme, respectively.

As shown in FIG. 26, each DVRB may be divided into two parts, and asecond one of the divided parts may be cyclically shifted by apredetermined gap (Gap=N_(DVRB)/N_(D)=50/2). In this case, only a partof the resource elements of an RBG0 consisting of PRBs are mapped by thefirst DVRB divided part, and only parts of the resource elements of RBG8and RBG9 each consisting of PRBs are mapped by the second DVRB dividedpart. For this reason, the RBG0, RBG8, and RBG9 cannot be applied to ascheme using a resource allocation on an RBG basis.

In order to solve this problem, the gap may be set to be a multiple ofthe number of RBs included in one RBG, namely, M_(RBG). That is, the gapmay satisfy a condition “Gap=M_(RBG)*k” (k is a natural number). Whenthe gap is set to satisfy this condition, it may have a value of, forexample, 27 (Gap=M_(RBG)*k=3*9=27). When Gap=27, each DVRB may bedivided into two parts, and a second one of the divided parts may becyclically shifted by the gap (Gap=27). In this case, only a part of theresource elements of the RBG0, which consists of PRBs, are mapped by thefirst DVRB divided part, and only a part of the resource elements of theRBG9, which consists of PRBs, are mapped by the second DVRB dividedpart. Accordingly, in the method of FIG. 27, the RBG8 can be applied toa scheme using a resource allocation on an RBG basis, different from themethod of FIG. 26.

In the method of FIG. 27, however, DVRB indexes paired in one PRB cannotbe paired in another PRB. Again referring to FIG. 26, the DVRB indexes 1and 26 paired in the PRB1 (2601) are also paired in the PRB26 (2603). Inthe method of FIG. 27, however, the DVRB indexes 1 and 27 paired in thePRB1 (2701) cannot be paired in the PRB25 or PRB27 (2703 or 2705).

In the case of FIG. 26 or 27, the DVRB1 and DVRB2 are mapped to thePRB1, PRB2, PRB25 and PRB26. In this case, parts of the resourceelements of the PRB1, PRB2, PRB25, and PRB26 are left without beingmapped.

In the case of FIG. 26, if the DVRB25 and DVRB26 are additionally mappedto PRBs, they completely fill the remaining spaces of the PRB1, PRB2,PRB25, and PRB26.

In the case of FIG. 27, however, if the DVRB25 and DVRB26 areadditionally mapped to PRBs, the DVRB25 and DVRB26 are mapped to thePRB0, PRB25, PRB26, and PRB49. As a result, the non-mapped resourceelement parts of the PRB1 and PRB2 are still left without being filledwith DVRBs. That is, the case of FIG. 27 has a drawback in that,usually, there are PRBs left without being mapped.

The problem occurs because the cyclic shift is performed such that a gapvalue does not equal to N_(DVRB)/N_(D). When N_(DVRB)/N_(D) is amultiple of M_(RBG), the above-described problem is solved because thecyclic shift corresponds to a multiple of M_(RBG).

Embodiment 13

In order to simultaneously solve the problems of FIGS. 26 and 27,accordingly, the number of RBs used for DVRBs, namely, N_(DVRB), islimited to a multiple of N_(D)·M_(RBG) in accordance with one embodimentof the present invention.

Embodiment 14

Meanwhile, it can be seen that, in the above cases, the first and seconddivided parts of each DVRB belong to different subsets, respectively. Inorder to make the two divided parts of each DVRB belong to the samesubset, the gap should be set to be a multiple of the square of M_(RBG)(M_(RBG) ²).

Therefore, in another embodiment of the present invention, the number ofRBs used for DVRBs, namely, N_(DVRB), is limited to a multiple ofN_(D)·M_(RBG) ², in order to make the two divided parts of each DVRBbelong to the same subset, and to make DVRBs be paired.

FIG. 28 illustrates the case in which N_(DVRB) is set to be a multipleof N_(D)·M_(RBG).

As shown in FIG. 28, the divided parts of DVRBs can always be paired inPRBs in accordance with a cyclic shift because the gap is a multiple ofM_(RBG)·N_(D). It is also possible to reduce the number of RBGs in whichthere are resource elements having parts not filled with DVRBs.

Embodiment 15

FIG. 29 illustrates the case in which DVRB indexes are interleaved inaccordance with the method of FIG. 28.

When DVRB indexes are interleaved as shown in FIG. 29, it may bepossible to set N_(DVRB) to a multiple of N_(D)·M_(RBG) when the DVRBindexes are mapped to PRBs. In this case, however, there may be anoccasion that the rectangular interleaver matrix is incompletely filledwith DVRB indexes, as shown in FIGS. 20A and 20B. In this case,accordingly, it is necessary to fill nulls in non-filled portions of therectangular interleaver matrix. In order to avoid the occasion requiringfilling of nulls in a block interleaver of degree D, it is necessary tolimit the number of RBs used for DVRBs to a multiple of D.

Accordingly, in one embodiment of the present invention, the gap is setto be a multiple of M_(RBG), and the second divided part of each DVRB iscyclically shifted by N_(RB)/N_(D) so that the DVRB indexes mapped toone PRB are paired. Also, in order to avoid filling of nulls in theblock interleaver, the number of RBs used for DVRBs, namely, N_(DVRB),is limited to a common multiple of N_(D)·M_(RBG) and D. If D is equal tothe diversity order (N_(DivOrder)=K·N_(D)) used in the interleaver inthis case, N_(DVRB) is limited to a common multiple of N_(D)·M_(RBG) andK·N_(D).

Embodiment 16

In another embodiment of the present invention, the gap is set to be amultiple of the square of M_(RBG), in order to make the two dividedparts of each DVRB be located on the same subset. Also, the seconddivided part of each DVRB is cyclically shifted by N_(RB)/N_(D) so thatthe DVRB indexes mapped to one PRB are paired. In order to avoid fillingof nulls in the block interleaver, the number of RBs used for DVRBs,namely, N_(DVRB), is limited to a common multiple of N_(D)·M_(RBG) ² andD. If D is set to the diversity order (N_(DivOrder)=K·N_(D)) used in theinterleaver in this case, N_(DVRB) is limited to a common multiple ofN_(D)·M_(RBG) ² and K·N_(D).

Embodiment 17

Meanwhile, FIG. 30 illustrates the case in which D is set to the numberof columns, namely, C, and C is set to N_(DivOrder)(N_(DivOrder)=K·N_(D)).

Of course, in the case of FIG. 30, writing is performed in such a mannerthat, after one column is completely filled, a next column is filled,and reading is performed in such a manner that, after one row iscompletely read, a next row is read.

In the embodiment of FIG. 30, N_(DVRB) is set such that consecutive DVRBindexes are assigned to the same subset. The illustrated rectangularinterleaver is configured such that consecutive indexes are filled inthe same subset when the number of rows is a multiple of M_(RBG) ².Since the number of rows, R, is N_(DVRB)/D (R=N_(DVRB)/D), the numberRBs used for DVRBs, namely, N_(DVRB), is limited to a multiple ofD·M_(RBG) ².

In order to map the two divided parts of each DVRB to the PRBs in thesame subset, the number of RBs used for DVRBs, namely, N_(DVRB), islimited to a common multiple of D·M_(RBG) ² and N_(D)·M_(RBG) ². WhenD=K·N_(D), N_(DVRB) is limited to K·N_(D)·M_(RBG) ² because the commonmultiple of K≮N_(D)·M_(RBG) ² and N_(D)·M_(RBG) ² is K·N_(D)·M_(RBG) ².

Finally, the number of RBs used for DVRBs may be a maximum number ofDVRBs satisfying the above-described limitations within the number ofPRBs in the entire system. RBs used for DVRBs may be used in aninterleaved manner.

Embodiment 18

Hereinafter, a mapping method using temporary PRB indexes when N_(PRB)and N_(DVRB) have different lengths in accordance with one embodiment ofthe present invention will be described.

FIG. 31 illustrates methods in which, when N_(PRB) and N_(DVRB) havedifferent lengths, the result of the mapping to PRBs performed using theDVRB interleaver of FIG. 29 is once again processed to make DVRBsfinally correspond to PRBs.

One of the schemes shown by (a), (b), (c), and (d) of FIG. 31 may beselected in accordance with the usage of system resources. In thisscheme, the value p in the above-described co-relational expressions ofDVRB and PRB indexes is defined as a temporary PRB index. In this case,a value o obtained after adding N_(offset) to p exceeding N_(threshold)is used as a final PRB index.

In this case, four alignment schemes respectively illustrated in FIG. 31may be expressed by Expression 12.

N _(threshold) =N _(DVRB)/2,N _(offset) =N _(PRB) ·N _(PRB) −N_(DVRB)  (a)

N _(threshold)=0,N _(offset)=0  (b)

N _(threshold)=0,N _(offset) =N _(PRB) −N _(DVRB)  (c)

N _(threshold)=0,N _(offset)=└(N _(PRB) −N _(DVRB))/2┘  (d)

or

N _(offset)=┌(N _(PRB) −N _(DVRB))/2┐  [Expression 12]

Here, (a) represents a justified alignment, (b) represents a leftalignment, (c) represents a right alignment, and (d) represents a centeralignment. Meanwhile, if a PRB index o is given, a DVRB index d can bederived from Expression 13, using a temporary PRB index p.

$\begin{matrix}{p = \left\{ \begin{matrix}{{o - N_{offset}},} & {{{when}\mspace{14mu} o} \geq {N_{threshold} + N_{offset}}} \\{o,} & {{{when}\mspace{14mu} o} < N_{threshold}}\end{matrix} \right.} & \left\lbrack {{Expression}\mspace{14mu} 13} \right\rbrack\end{matrix}$

On the other hand, if the DVRB index d is given, a PRB index o can bederived from Expression 14, using a temporary PRB index p.

$\begin{matrix}{o_{i,d} = \left\{ \begin{matrix}{{p_{i,d} + N_{offset}},} & {{{when}\mspace{14mu} p_{i,d}} \geq N_{threshold}} \\{p_{i,d},} & {{{when}\mspace{14mu} p_{i,d}} < N_{threshold}}\end{matrix} \right.} & \left\lbrack {{Expression}\mspace{14mu} 14} \right\rbrack\end{matrix}$

Embodiment 19

Hereinafter, a mapping method capable of increasing N_(DVRB) to amaximum while satisfying the gap limitations in accordance with oneembodiment of the present invention will be described.

The previous embodiments have proposed interleaver structures forreducing the number of PRBs, in which there are resource elements havingparts not filled with DVRBs, where the RBG scheme and/or the subsetscheme is introduced for allocation of LVRBs. The previous embodimentshave also proposed methods for limiting the number of RBs used forDVRBs, namely, N_(DVRB).

However, as the limitation condition caused by M_(RBG) becomes morestrict, the limitation on the number of RBs usable for DVRBs, namely,N_(DVRB), among the total number of PRBs, namely, N_(PRB), increases.

FIG. 32 illustrates the case using a rectangular interleaver havingconditions of “N_(PRB)=32”, “M_(RBG)=3”, “K=2”, and “N_(D)=2”.

When N_(DVRB) is set to be a multiple of N_(D)·M_(RBG) ² (=18), toenable the two divided parts of each DVRB to be mapped to PRBs belongingto the same subset, while having a maximum value not exceeding N_(PRB),the set N_(DVRB) is equal to 18 (N_(DVRB)=18).

In order to enable the two divided parts of each DVRB to be mapped toPRBs belonging to the same subset in the case of FIG. 32, N_(RB) is setto be 18 (N_(wv)=18). In this case, 14 RBs (32−18=14) cannot be used forDVRBs.

In this case, it can be seen that N_(gap) is 9 (N_(gap)=18/2=9), and theDVRB0 is mapped to respective first RBs of the RBG0 and RBG3 belongingto the same subset.

Accordingly, the present invention proposes a method for satisfying gaplimitation conditions when N_(D)=2 by setting an offset and a thresholdvalue, to which the offset will be applied, as previously proposed,without directly reflecting the gap limitation conditions on N_(RB).

1) First, desired gap limitation conditions are set. For example, thegap may be set to a multiple of M_(RBG) or a multiple of M_(RBG) ².

2) Next, a numeral nearest to N_(PRB)/2 among numerals satisfying thegap limitation conditions is set as N_(gap).

3) When N_(gap) is smaller than N_(PRB)/2, the same mapping as that ofFIG. 20 is used.

4) When N_(gap) is equal to or larger than N_(PRB)/2, and filling ofnulls in the interleaver is allowed, N_(DVRB) is set such thatN_(DVRB)=(N_(PRB)−N_(gap))·2. However, when no filling of nulls in theinterleaver is allowed, N_(DVRB) is set such thatN_(DVRB)=└min(N_(PRB)−N_(gap),N_(gap))·2/C┘·C.

5) An offset is applied to a half or more of N_(DVRB). That is, areference value for the application of the offset, namely, N_(threshold)is set such that N_(threshold)=N_(DVRB)/2.

6) The offset is set such that temporary PRBs, to which the offset isapplied, satisfy the gap limitation conditions.

That is, N_(offset) is set such that N_(offset)=N_(gap)−N_(threshold).

This may be expressed by Expression 15 as a generalized mathematicexpression.

1. Setting of N_(gap) according to gap conditions:

-   -   Under an M_(RBG) ²-multiple condition:

N _(gap)=round(N _(PRB)/(2·M _(RBG) ²))·M _(RBG) ²

-   -   Under an M_(RBG)-multiple condition:

N _(gap)=round(N _(PRB)/(2·M _(RBG)))·M _(RBG)

2. Setting of N_(DVRB):

-   -   Under a null-allowed condition:

N _(DVRB)=min(N _(PRB) −N _(gap) ,N _(gap))·2

Under no null-allowed condition:

N _(DVRB)=└min(N _(PRB) −N _(gap) ,N _(gap))·2/C┘·C  [Expression 15]

3. Setting of N_(threshold): N_(threshold)=N_(DVRB)/2

4. Setting of N_(offset): N_(offset)=N_(gap)−N_(threshold)

FIG. 33 illustrates application of a DVRB mapping rule proposed in thepresent invention when N_(PRB)=32, M_(RBG)=3, and a rectangularinterleaver of K=2 and N_(D)=2.

When N_(gap) is set such that it is a multiple of M_(RBG) ² (=9) whilebeing nearest to N_(PRB)/2, in order to map the two divided parts ofeach DVRB to PRBs belonging to the same subset, respectively, the setN_(gap) is equal to 18 (N_(gap)=18). In this case, 28 RBs ((32−18)×2=28)are used for DVRBs. That is, conditions of “N_(DVRB)=28”,“N_(threshold)=28/2=14”, and “N_(offset)=18−14=4” are established.Accordingly, temporary PRB indexes, to which DVRB indexes interleaved bythe rectangular interleaver are mapped, are compared with N_(threshold).When N_(offset) is added to temporary PRB indexes satisfyingN_(threshold), a result as shown in FIG. 33 is obtained. Referring toFIG. 33, it can be seen that the two divided parts of the DVRB0 aremapped to respective first RBs of the RBG0 and RBG6 belonging to thesame subset. When this method is compared with the method of FIG. 32, itcan also be seen that the number of RBs usable for DVRBs is increasedfrom 18 to 28. Since the gap is also increased, the diversity in theDVRB mapping can be further increased.

Embodiment 20

Hereinafter, a mapping method capable of increasing N_(DVRB) to amaximum while mapping consecutive indexes to specific positions inaccordance with one embodiment of the present invention will bedescribed.

Where one UE is allocated several DVRBs, the allocated DVRBs areconsecutive DVRB. In this case, accordingly, it is preferable to setcontiguous indexes such that they are positioned at intervals of amultiple of M_(RBG) or a multiple of M_(RBG) ², for scheduling of LVRBs,similarly to the setting of the gap. When it is assumed, in this case,that the degree of the interleaver is equal to the number of columns,namely, C, the number of rows, namely, R, should be a multiple ofM_(RBG) or a multiple of M_(RBG) ². Accordingly, the size of theinterleaver, namely, N_(interleaver)=C·R, should be a multiple ofC·M_(RBG) or a multiple of C·M_(RBG) ². Thus, if N_(DVRB) is previouslygiven, a minimum interleaver size satisfying the above conditions can bederived as follows.

Under no multiple condition, N_(interleaver)=┌N_(DVRB)/C┐·C.

-   -   In this case, accordingly, R=N_(interleaver)/C=┌N_(DVRB)/C┐

Under the C·M_(RBG)-multiple condition,N_(interleaver)=┌D_(DVRB)/(C·M_(RBG))┐·C·M_(RBG).

-   -   In this case, accordingly,        R=N_(interleaver)/C=┌N_(DVRB)/(C·M_(RBG))┐·M_(RBG).

Under the C·M_(RBG) ²-multiple condition,N_(interleaver)=┌N_(DVRB)/(C·M_(RBG) ²)┐·C·M_(RBG) ².

-   -   In this case, accordingly,        R=N_(interleaver)/C=┌N_(DVRB)/(C·M_(RBG) ²)┐·M_(RBG) ².

The number of nulls included in the interleaver is as follows.

Under no multiple condition,

N _(null) =N _(interleaver) −N _(DVRB) =┌N _(DVRB) /C┐·C−N _(DVRB).

Under the C·M_(RBG)-multiple condition,

N _(null) =N _(interleaver) −N _(DVRB) =┌N _(DVRB)/(C·M _(RBG))┌·C·M_(RBG) −N _(DVRB).

Under the C·M_(RBG) ²-multiple condition,

N _(null) =N _(interleaver) −N _(DVRB) =┌N _(DVRB) /C·M _(RBG) ²)┐·C·M_(RBG) ² −N _(DVRB).

The exemplary embodiments described hereinabove are combinations ofelements and features of the present invention. The elements or featuresmay be considered selective unless otherwise mentioned. Each element orfeature may be practiced without being combined with other elements orfeatures. Further, the embodiments of the present invention may beconstructed by combining parts of the elements and/or features.Operation orders described in the embodiments of the present inventionmay be rearranged. Some constructions of any one embodiment may beincluded in another embodiment and may be replaced with correspondingconstructions of another embodiment. It is apparent that the presentinvention may be embodied by a combination of claims which do not havean explicit cited relation in the appended claims or may include newclaims by amendment after application.

The embodiments of the present invention may be achieved by variousmeans, for example, hardware, firmware, software, or a combinationthereof. In a hardware configuration, the embodiments of the presentinvention may be implemented by one or more application specificintegrated circuits (ASICs), digital signal processors (DSPs), digitalsignal processing devices (DSPDs), programmable logic devices (PLDs),field programmable gate arrays (FPGAs), processors, controllers,microcontrollers, microprocessors, etc.

In a firmware or software configuration, the embodiments of the presentinvention may be achieved by a module, a procedure, a function, etc.performing the above-described functions or operations. A software codemay be stored in a memory unit and driven by a processor. The memoryunit is located at the interior or exterior of the processor and maytransmit data to and receive data from the processor via various knownmeans.

INDUSTRIAL APPLICABILITY

The present invention is applicable to a transmitter and a receiver usedin a broadband wireless mobile communication system.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A method for transmitting downlink data usingresource blocks at a base station in a wireless mobile communicationsystem, the method comprising: transmitting downlink data mapped tophysical resource blocks (PRBs) to a user equipment, wherein virtualresource blocks (VRBs) are mapped to the PRBs for each of a first slotand a second slot of a subframe, wherein indexes of PRBs of the firstslot are shifted for a predetermined gap with respect to indexes of PRBsof the second slot, and wherein an index of a PRB which is mapped to aVRB is determined by using N_(gap) and N_(DVRB), where N_(gap) is avalue of the predetermined gap and N_(DVRB) is a number of the VRBs. 2.The method according to claim 1, wherein indexes of the VRBs areinterleaved by a block interleaver, wherein an index o_(1,d) of one ofthe PRBs of the first slot which is mapped to an index d of one of theVRBs is set to p_(1,d)+N_(gap)−N_(DVRB)/2, when a temporary indexp_(1,d) of the one of the PRBs of the first slot is greater than orequal to N_(DVRB/)2, wherein an index o_(2,d) of one of the PRBs of thesecond slot which is mapped to the index d is set top_(2,d)+N_(gap)−N_(DVRB)/2, when a temporary index p_(2,d) of the one ofthe PRBs of the second slot is greater than or equal to N_(DVRB/)2, andwherein d is an integer value from 0 to N_(DVRB)−1, and p_(1,d),p_(2,d), o_(1,d), and o_(2,d) are integer values from 0 to N_(PRB)−1,where N_(PRB) is a number of the PRBs.
 3. The method according to claim2, wherein the temporary index p_(1,d) is defined as following equation1, and the temporary index p_(2,d) is defined as following equation 2,$\begin{matrix}{\mspace{20mu} {p_{1,d} = \left\{ {{{\begin{matrix}{p_{1,d}^{\prime},} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} = {0\mspace{14mu} {or}}} \\\begin{pmatrix}{d < {N_{DVRB} - {N_{null}\mspace{14mu} {and}}}} \\{{{mod}\left( {d,C} \right)} < 2}\end{pmatrix}\end{matrix} \\{{p_{1,d}^{\prime} - {N_{null}/2}},} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} \neq {0\mspace{14mu} {and}}} \\\begin{pmatrix}{d < {N_{DVRB} - {N_{null}\mspace{14mu} {and}}}} \\{{{mod}\left( {d,C} \right)} \geq 2}\end{pmatrix}\end{matrix}\end{matrix}\mspace{20mu} {where}\mspace{14mu} p_{1,d}^{\prime}} = {{{{mod}\left( {d,C} \right)} \cdot R} + \left\lfloor {d/C} \right\rfloor}},{p_{1,d} = \left\{ {{{\begin{matrix}{{p_{1,d}^{\prime} - R + {N_{null}/2}},} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} \neq {0\mspace{14mu} {and}}} \\\begin{pmatrix}{d \geq {N_{DVRB} - {N_{null}\mspace{14mu} {and}}}} \\{{{mod}\left( {d,{C/2}} \right)} = 0}\end{pmatrix}\end{matrix} \\{{p_{1,d}^{\prime} - R},} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} \neq {0\mspace{14mu} {and}}} \\\begin{pmatrix}{d \geq {N_{DVRB} - {N_{null}\mspace{14mu} {and}}}} \\{{{mod}\left( {d,{C/2}} \right)} = 1}\end{pmatrix}\end{matrix}\end{matrix}\mspace{20mu} {where}\mspace{14mu} p_{1,d}^{\prime}} = {{{{{mod}\left( {d,{C/2}} \right)} \cdot 2}R} + \left\lfloor {2{d/C}} \right\rfloor}},} \right.}} \right.}} & \left\lbrack {{equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$p _(2,d)=mod(p _(1,d) +N _(DVRB)/2,N _(DVRB)), and  [equation 2] whereinR is a number of rows of the block interleaver, C is a number of columnsof the block interleaver, and ‘mod’ represents a modulo operation. 4.The method according to claim 2, wherein a number of rows (R) of theblock interleaver is defined as following equation 1, and a number ofnulls (N_(null)) filled in the block interleaver is defined as followingequation 2,R=N _(interleaver) /C=┌D _(DVRB)/(C·M _(RBG))┐·M _(RBG)N _(interleaver) =┌N _(DVRB)/(C·M _(RBG))┐·C·M _(RBG)  [equation 1]N _(null) =N _(interleaver) −N _(DVRB)=┌_(DVRB)/(C·M _(RBG))┐·C·M _(RBG)−N _(DVRB), and  [equation 2] wherein C is a number of columns of theblock interleaver, and M_(RBG) is a number of consecutive PRBs in oneresource block group (RBG).
 5. The method according to claim 2, whereinN_(DVRB) is defined as following equation 3,N _(DVRB)=min(N _(PRB) −N _(gap) ,N _(gap))·2  [equation 3]
 6. Themethod according to claim 1, wherein N_(gap) is a multiple of P², whereP is a number of consecutive PRBs in one RBG and is a function of asystem bandwidth.
 7. A base station configured to transmit downlink datausing resource blocks in a wireless mobile communication system, thebase station comprising: a processor configured to control atransmitting operation of the base station; and a memory unit driven bythe processor, wherein the processor is further configured to transmitdownlink data mapped to PRBs to a user equipment, wherein VRBs aremapped to the PRBs for each of a first slot and a second slot of asubframe, wherein indexes of PRBs of the first slot are shifted for apredetermined gap with respect to indexes of PRBs of the second slot,and wherein an index of a PRB which is mapped to a VRB is determined byusing N_(gap) and N_(DVRB), where N_(gap) is a value of thepredetermined gap and N_(DVRB) is a number of the VRBs.
 8. The basestation according to claim 7, wherein indexes of the VRBs areinterleaved by a block interleaver of the base station, wherein an indexo_(1,d) of one of the PRBs of the first slot which is mapped to an indexd of one of the VRBs is set to p_(1,d)+N_(gap)−N_(DVRB)/2, when atemporary index p_(1,d) of the one of the PRBs of the first slot isgreater than or equal to N_(DVRB)/2, wherein an index o_(2,d) of one ofthe PRBs of the second slot which is mapped to the index d is set top_(2,d)+N_(gap)−N_(DVRB)/2, when a temporary index p_(2,d) of the one ofthe PRBs of the second slot is greater than or equal to N_(DVRB)/2, andwherein d is an integer value from 0 to N_(DVRB)−1, and p_(1,d),p_(2,d), o_(1,d), and o_(2,d) are integer values from 0 to N_(PRB)−1,where N_(PRB) is a number of the PRBs.
 9. The base station according toclaim 8, wherein the temporary index p_(1,d) is defined as followingequation 1, and the temporary index p_(2,d) is defined as followingequation 2, $\begin{matrix}{\mspace{20mu} {p_{1,d} = \left\{ {{{\begin{matrix}{p_{1,d}^{\prime},} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} = {0\mspace{14mu} {or}}} \\\begin{pmatrix}{d < {N_{DVRB} - {N_{null}\mspace{14mu} {and}}}} \\{{{mod}\left( {d,C} \right)} < 2}\end{pmatrix}\end{matrix} \\{{p_{1,d}^{\prime} - {N_{null}/2}},} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} \neq {0\mspace{14mu} {and}}} \\\begin{pmatrix}{d < {N_{DVRB} - {N_{null}\mspace{14mu} {and}}}} \\{{{mod}\left( {d,C} \right)} \geq 2}\end{pmatrix}\end{matrix}\end{matrix}\mspace{20mu} {where}\mspace{14mu} p_{1,d}^{\prime}} = {{{{mod}\left( {d,C} \right)} \cdot R} + \left\lfloor {d/C} \right\rfloor}},{p_{1,d} = \left\{ {{{\begin{matrix}{{p_{1,d}^{\prime} - R + {N_{null}/2}},} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} \neq {0\mspace{14mu} {and}}} \\\begin{pmatrix}{d \geq {N_{DVRB} - {N_{null}\mspace{14mu} {and}}}} \\{{{mod}\left( {d,{C/2}} \right)} = 0}\end{pmatrix}\end{matrix} \\{{p_{1,d}^{\prime} - R},} & \begin{matrix}{{{when}\mspace{14mu} N_{null}} \neq {0\mspace{14mu} {and}}} \\\begin{pmatrix}{d \geq {N_{DVRB} - {N_{null}\mspace{14mu} {and}}}} \\{{{mod}\left( {d,{C/2}} \right)} = 1}\end{pmatrix}\end{matrix}\end{matrix}\mspace{20mu} {where}\mspace{14mu} p_{1,d}^{\prime}} = {{{{{mod}\left( {d,{C/2}} \right)} \cdot 2}R} + \left\lfloor {2{d/C}} \right\rfloor}},} \right.}} \right.}} & \left\lbrack {{equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$p _(2,d)=mod(p _(1,d) +N _(DVRB)/2,N _(DVRB)), and  [equation 2] whereinR is a number of rows of the block interleaver, C is a number of columnsof the block interleaver, and ‘mod’ represents a modulo operation. 10.The base station according to claim 8, wherein a number of rows (R) ofthe block interleaver is defined as following equation 1, and a numberof nulls (N_(null)) filled in the block interleaver is defined asfollowing equation 2,R=N _(interleaver) /C=┌N _(DVRB)/(C·M _(RBG))┐·M _(RBG)N _(interleaver) =┌N _(DVRB)/(C·M _(RBG))┐·C·M _(RBG)  [equation 1]N _(null) =N _(interleaver) −N _(DVRB) =┌N _(DVRB)/(C·MR _(RBG))┐·C·M_(RBG) −N _(DVRB), and  [equation 2] wherein C is a number of columns ofthe block interleaver, and M_(RBG) is a number of consecutive PRBs inone resource block group (RBG).
 11. The base station according to claim8, wherein N_(DVRB) is defined as following equation 3,N _(DVRB)=min(N _(PRB) −N _(gap) ,N _(gap))·2  [equation 3]
 12. The basestation according to claim 7, wherein N_(gap) is a multiple of P², whereP is a number of consecutive PRBs in one RBG and is a function of asystem bandwidth.